JP2005196131A - Capacitive load driver and plasma display carrying same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driver capable of effectively suppressing the reactive power due to charging and discharging of a capacitive load at a number of parts fewer than that of the conventional devices without exertion of an adverse influence on another circuit parts, and reducing the power consumption of the whole system, as the driver of the capacitive load, such as a PDP. <P>SOLUTION: Sustain electrodes (X 1, X 2, ...) of a PDP (20) are grounded. A PFC converter (40) converts an alternating voltage into a DC voltage (Vs) and applies it directly to a PDP driver (10). A discharge sustaining pulse generating section (1) converts the DC voltage (Vs) into a primary voltage pulse (VF), and applies it to a primary winding (2 a) of a transformer (2). The transformer (2) converts the primary voltage pulse (VF) into a discharge sustaining voltage pulse (Vp), and applies it to scan electrodes (Y 1, Y 2, ...) of the PDP (20) through an initializing/scanning pulse generating section (3). An inductor (L) is connected in parallel with a secondary winding (2 b) of the transformer (2). The inductor (L) resonates with the panel capacitance of the PDP (20) at the rising and falling edges of the discharge sustain voltage pulse (Vp). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a drive device for a capacitive load such as a plasma display panel (PDP).

  A plasma display is a display device that utilizes a light emission phenomenon associated with gas discharge. A plasma display panel (PDP) is more advantageous than other display devices in terms of a large screen, a thin profile, and a wide viewing angle. PDPs are roughly classified into a DC type that operates with a DC pulse and an AC type that operates with an AC pulse. The AC type PDP has a particularly high luminance and a simple structure. Therefore, the AC type PDP is suitable for mass production and pixel definition and is widely used.

  FIG. 42 is a block diagram showing a configuration of a conventional plasma display (see, for example, Patent Documents 1, 2, and 3). The conventional plasma display includes a PDP 20, a power factor correction (PFC) converter 40, a PDP driving device 100, and a control unit 30.

The PDP 20 is, for example, an AC type, and has a three-electrode surface discharge type structure. Address electrodes A1, A2, A3,... Are arranged on the back substrate of the PDP 20 in the vertical direction of the panel. On the front substrate of PDP 20, sustain electrodes X1, X2, X3,... And scan electrodes Y1, Y2, Y3,... Are alternately arranged in the horizontal direction of the panel. Since the sustain electrodes X1, X2, X3,... Are connected to each other, the potentials are substantially equal. The address electrodes A1, A2, A3,... And the scan electrodes Y1, Y2, Y3,.
Discharge cells are installed at a pair of sustain electrodes and scan electrodes adjacent to each other (for example, a pair of sustain electrode X2 and scan electrode Y2) and an intersection P (shaded portion shown in FIG. 42) of an address electrode (for example, A2). The On the surface of the discharge cell, a layer made of a dielectric (dielectric layer), a layer for protecting the electrode and the dielectric layer (protective layer), and a layer containing a fluorescent substance (fluorescent layer) are provided. Gas is sealed inside the discharge cell. When a predetermined pulse voltage is applied between the sustain electrode, the scan electrode, and the address electrode, discharge occurs in the discharge cell. At that time, gas molecules in the discharge cell are ionized and emit ultraviolet rays. The ultraviolet rays excite the fluorescent material on the surface of the discharge cell to generate fluorescence. Thus, the discharge cell emits light.

  The PFC converter 40 converts AC power from an external commercial AC power source AC into DC power. The PFC converter 40 then keeps the power factor substantially equal to 1 for the input from the commercial AC power source AC.

The PDP driver 100 includes a DC-DC converter 101, a sustain electrode driver 102, a scan electrode driver 103, and an address electrode driver 104.
The DC-DC converter 101 converts the output voltage of the PFC converter 40 into a predetermined DC voltage Vc, and keeps the DC voltage Vc constant. The DC-DC converter 101 is generally an insulation type, and insulates between the input high voltage portion (the portion surrounded by the broken line shown in FIG. 42) and the output PDP 20. Thereby, the PDP driving device 100 sufficiently secures safety.
Each of the sustain electrode driver 102, the scan electrode driver 103, and the address electrode driver 104 includes a switch element, and generates a pulse voltage by switching the switch elements.
The sustain electrode driving unit 102 is connected to the sustain electrodes X1, X2, X3,... Of the PDP 20, converts the output voltage of the DC-DC converter 101 into a predetermined pulse voltage, and the sustain electrodes X1, X2, X3,. Apply simultaneously.
The scan electrode driving unit 103 is connected to the scan electrodes Y1, Y2, Y3,... Of the PDP 20, converts the output voltage of the DC-DC converter 101 into a predetermined pulse voltage, and the scan electrodes Y1, Y2, Y3,. Apply individually.
The address electrode driver 104 is connected to the address electrodes A1, A2, A3,... Of the PDP 20, and applies a predetermined pulse voltage to them individually.

The control unit 30 controls switching of each of the sustain electrode driving unit 102, the scan electrode driving unit 103, and the address electrode driving unit 104. The switching control follows an ADS (Address Display-period Separation) system.
The ADS method is a kind of subfield method. In the subfield method, one field of an image is divided into a plurality of subfields. Each subfield includes an initialization period, an address period, and a discharge sustain period. Particularly in the ADS system, the three periods are set in common for all the discharge cells of the PDP 20.

In the initialization period, an initialization pulse voltage is applied between the sustain electrodes X1, X2, X3,... Of the PDP 20 and the scan electrodes Y1, Y2, Y3,. Thereby, wall charges are made uniform in all the discharge cells.
In the address period, the scan pulse voltage is sequentially applied to the scan electrodes Y1, Y2, Y3,. At the same time, signal pulse voltages are applied to some of the address electrodes A1, A2, A3,. Here, the address electrode to which the signal pulse voltage is to be applied is selected based on the video signal input from the outside. When a scan pulse voltage is applied to one of the scan electrodes Y2 and a signal pulse voltage is applied to one of the address electrodes A2, a discharge is performed at a discharge cell located at the intersection P between the scan electrode Y2 and the address electrode A2. Occurs. The discharge accumulates wall charges on the surface of the discharge cell P.
In the discharge sustain period, the discharge sustain pulse voltage is applied simultaneously and periodically between the sustain electrodes X1, X2, X3,... And the scan electrodes Y1, Y2, Y3,. At that time, in the discharge cell P in which wall charges are accumulated during the address period, the discharge by the gas is maintained and light emission occurs. Since the length of the discharge sustaining period is different for each subfield, the light emission time per field of the discharge cell, that is, the luminance of the discharge cell is adjusted by selecting the subfield to emit light.
Based on the video signal, the control unit 30 determines an address electrode and a subfield to which the signal pulse voltage is applied. As a result, an image corresponding to the image signal is reproduced on the PDP 20.

  The light emission of each discharge cell of the PDP requires the accumulation of wall charges. That is, the PDP is a capacitive load. In the PDP, as in the above-described three-electrode surface discharge structure, a large number of electrodes run vertically and horizontally on the panel and are close to each other. Therefore, the PDP has a large stray capacitance. In particular, the stray capacitance (hereinafter referred to as panel capacitance) between the sustain electrode and the scan electrode is large. When a pulse voltage is applied between the sustain electrode and the scan electrode, the panel capacitance is charged / discharged. Due to the charging current and the discharging current, power is consumed by the respective resistances of the circuit elements of the PDP driving device, the sustain electrodes and the scanning electrodes of the PDP, and the lead wires. The power consumption is reactive power and does not contribute to the light emission of the discharge cell. The larger the size of the PDP, the larger the length and number of sustain electrodes and scan electrodes, and the larger the panel capacity. Therefore, the reduction of the reactive power is indispensable for achieving both a large screen and power saving of the PDP.

  As a PDP drive device that suppresses the reactive power, for example, a drive device using a push-pull inverter as a pulse generator is known (see, for example, FIG. 10 of Patent Document 1). FIG. 43 is an equivalent circuit diagram of the pulse generator 102 and the PDP 20. The pulse generating unit 102 includes a push-pull inverter unit 102a and an inductor L. Sustain electrode X and scan electrode Y of PDP 20 are connected to the output side of pulse generator 102. Here, the equivalent circuit of the PDP 20 is represented only by the panel capacitance Cp, and the path of the current flowing through the PDP 20 when discharging in the discharge cells is omitted.

  The control unit 30 (see FIG. 42) alternately turns on and off the two switch elements Q1 and Q2 of the inverter unit 102a. Thereby, the polarity of the secondary voltage of the transformer Tr is periodically inverted. As a result, an AC pulse voltage with a constant period is applied to the panel capacitance Cp. In particular, the control unit 30 adjusts the length of the dead time (period in which the two switch elements Q1 and Q2 are simultaneously turned off), and resonates the inductor L and the panel capacitance Cp during that period. Due to the resonance, the polarity of the voltage across the panel capacitance Cp is reversed with almost no power consumption. That is, during the resonance period, power consumed by the circuit elements of the pulse generation unit 102, the sustain electrodes X and the scan electrodes Y of the PDP 20, and the resistances (not shown) of the lead wires are suppressed. Thus, reactive power resulting from charging / discharging of the panel capacitance Cp is reduced.

  In the pulse generator 102, the secondary winding of the transformer Tr, the inductor L, and the panel capacitance Cp are always connected in series. Therefore, the inductor L and the panel capacitance Cp resonate even outside the above resonance period. For example, when the PDP 20 emits light, the discharge current flowing through the PDP 20 causes resonance between the inductor L and the panel capacitance Cp. This resonance adversely affects the image of the PDP 20. Furthermore, the withstand voltage of the circuit elements of the PDP driving device must be high enough to allow ringing associated with the resonance.

The resonance between the inductor L and the panel capacitance Cp is preferably limited only to the resonance period. As such a pulse generator, a pulse generator including a power recovery unit is known (see, for example, Patent Document 2 FIG. 5 and Patent Document 3 FIG. 2).
FIG. 44 is an equivalent circuit diagram of the pulse generator 102 and the PDP 20 disclosed in Patent Document 2. The pulse generation unit 102 includes a full-bridge inverter unit 102a and two similar power recovery units 102b and 102c.
FIG. 45 is an equivalent circuit diagram of the pulse generator 102 and the PDP 20 disclosed in Patent Document 3. The pulse generation unit 102 includes a full bridge type inverter unit 102a and a power recovery unit 102d.
In any pulse generation unit 102, the sustain electrode X and the scan electrode Y of the PDP 20 are connected to the output side of the inverter unit 102a (the equivalent circuit of the PDP 20 is represented only by the panel capacitance Cp).

The control unit 30 (see FIG. 42) turns on and off the switch element of the pulse generation unit 102 at a predetermined timing. Thereby, an AC pulse voltage having a constant period is applied to the panel capacitance Cp.
In particular, the control unit 30 turns on the switch element of the power recovery unit (102b, 102c, or 102d) during a period in which the voltage across the panel capacitance Cp changes, thereby causing the inductor L and the panel capacitance Cp to resonate. The resonance inverts the voltage across the panel capacitance Cp with almost no power consumption. That is, during the resonance period, power consumed by the circuit elements of the pulse generation unit 102, the sustain electrodes X and the scan electrodes Y of the PDP 20, and the resistances (not shown) of the lead wires are suppressed.
Thus, reactive power resulting from charging / discharging of the panel capacitance Cp is reduced. Furthermore, since the resonance between the inductor L and the panel capacitance Cp is limited to the above-described resonance period, the image of the PDP 20 is not adversely affected. In addition, the ringing associated with the resonance does not have to be taken into account when the PDP 20 emits light, so that the withstand voltage of the circuit elements of the PDP driving device can be reduced.

Japanese Patent Laid-Open No. 5-191977 Japanese Examined Patent Publication No. 7-109542 Japanese Patent Laid-Open No. 11-344952

A plasma display is desired to have a large screen, a thin shape, a light weight, and power saving. However, the enlargement of the screen increases the reactive power due to the charging / discharging of the panel capacity. Therefore, power saving is prevented. The increase in the reactive power further increases the current capacity of the circuit element of the PDP driving device or increases the breakdown voltage. As a result, since the size of the circuit element increases, the mounting area of the entire PDP driving device increases. Thus, thinning and weight reduction are hindered.
In order to simultaneously achieve an increase in screen size, thickness reduction, weight reduction, and power saving of the plasma display, it is desirable to configure the PDP driving device capable of effectively suppressing the reactive power with a smaller number of components.

  As a drive device for a capacitive load such as a PDP, the present invention effectively reduces the reactive power resulting from charging / discharging of the capacitive load with respect to other circuit parts with a smaller number of parts than the conventional drive device. An object of the present invention is to provide a drive device that can be suppressed without adverse effects and that can reduce the power consumption of the entire system combined with the load.

A capacitive load driving device according to the present invention is a device for applying a predetermined pulse voltage to a capacitive load,
A pulse generator that includes a switch element and converts a predetermined DC voltage into a primary pulse voltage by switching of the switch element; and
A transformer including a primary winding connected to the pulse generator and a secondary winding connected to the capacitive load, and converts the primary pulse voltage to the pulse voltage;
Have

Further, the present invention can be understood from the following three viewpoints regarding the means of power recovery.
According to a first aspect of the present invention, the transformer includes an exciting inductance that resonates with a capacitive load.
According to a second aspect of the present invention, the capacitive load driving device further comprises:
An auxiliary inductor connected in parallel with the secondary winding of the above transformer and resonating with a capacitive load;
Have
According to a third aspect of the present invention, the capacitive load driving device further comprises:
A power recovery unit including an inductor and a switch unit for passing a current associated with resonance between the inductor and the capacitive load during an ON period;
Have

The capacitive load is preferably a plasma display panel (PDP). At that time, the capacitive load driving device according to the present invention is mounted as a PDP driving device in the following plasma display. The plasma display
A rectifying unit for converting an AC voltage from an external power source into a predetermined DC voltage;
The PDP driving device for converting the DC voltage into a predetermined pulse voltage; and
A PDP including a discharge cell that emits light by discharge of gas enclosed therein, and a plurality of electrodes that apply the pulse voltage to the discharge cell;
Have

The above capacitive load driving device according to the present invention has a transformer on the output side of the pulse generator. The transformer appropriately adjusts the level of the pulse voltage and applies it to the capacitive load.
Therefore, unlike the conventional driving device, the above-described capacitive load driving device according to the present invention may not include a DC-DC converter on the input side of the pulse generation unit. Thereby, the number of parts is small and the mounting area is small.
Furthermore, since power loss due to the DC-DC converter is eliminated, power consumption is low.
In addition, a high voltage from an external power source may be directly applied to the pulse generator. At that time, the current in the pulse generator is smaller than that in the conventional apparatus. Therefore, the current capacity of the circuit element may be smaller than the conventional one. As a result, the capacitive load driving device according to the present invention is easier to miniaturize than the conventional device.
The transformer further insulates between the primary high voltage section and the secondary capacitive load. Thereby, the above-described capacitive load driving device according to the present invention can sufficiently ensure safety.

  In the above capacitive load driving device according to the present invention, the transformer exciting inductance, the auxiliary inductor connected in parallel with the secondary winding of the transformer, or the inductor of the power recovery unit resonates with the capacitive load. Due to the resonance, the pulse voltage changes with little power consumption. Thus, reactive power due to charging / discharging of the capacitive load is effectively suppressed.

According to the first or second aspect of the present invention, the exciting inductance or auxiliary inductor of the transformer resonates with the capacitive load. They are equivalent to an inductor connected in parallel with the secondary winding of the transformer. Therefore, the resonance period is limited to the rising period and the falling period of the pulse voltage or the primary pulse voltage.
When the capacitive load is a PDP, the discharge current of the PDP does not particularly flow through the transformer excitation inductance and the auxiliary inductor. Therefore, the above resonance does not adversely affect the image of the PDP. Furthermore, the ringing associated with the resonance does not have to be taken into consideration when the PDP emits light. Therefore, the breakdown voltage of the circuit element may be low.
As a result, when the exciting inductance or auxiliary inductor of the transformer resonates with the capacitive load, the power recovery unit may not be included. Thereby, the capacitive load driving device according to the present invention has a smaller number of parts and a smaller mounting area.

According to the first or second aspect of the present invention, when the exciting inductance or auxiliary inductor of the transformer starts to resonate with the capacitive load, current is already flowing through the exciting inductance or auxiliary inductor. Therefore, the rise and fall of the pulse voltage are fast. As a result, the maximum number of pulses that can be applied to the capacitive load in a certain period increases.
When the capacitive load is a PDP, the discharge sustain period is particularly shortened by shortening the rising period and the falling period of the pulse voltage. Therefore, the number of subfields per field can be easily increased. Thus, when the above-described capacitive load driving device according to the present invention is used as a PDP driving device, it is easy to further refine the gradation of the PDP, that is, to further improve the image quality.

  According to the second aspect of the present invention, the auxiliary inductor resonates with the capacitive load. Preferably, the inductance of the auxiliary inductor is set sufficiently smaller than the exciting inductance of the transformer. Thereby, the resonance current mainly flows through the auxiliary inductor and hardly flows through the transformer. Accordingly, the copper loss of the transformer is reduced. Thus, power consumption is further reduced.

  According to the third aspect of the present invention, the inductor of the power recovery unit resonates with the capacitive load. Further, the resonance period is accurately controlled by turning on and off the switch section. Preferably, the switch unit makes the ON period coincide with the rising period and the falling period of the pulse voltage or the primary pulse voltage. More preferably, the inductor and the switch unit are connected in series in the power recovery unit. At that time, no current flows through the inductor during the OFF period of the switch section. Thus, the resonance period between the inductor and the capacitive load is reliably limited to a desired period. Therefore, the power loss is particularly small among the means for collecting power.

According to the third aspect of the present invention, the power recovery unit may be connected to the primary winding of the transformer or to the secondary winding.
Particularly when the power recovery unit is connected to the secondary winding of the transformer, the resonance current is not substantially upstream to the secondary winding of the transformer. Therefore, no copper loss occurs in the transformer during the resonance period. As a result, power consumption is reduced.
Furthermore, since the effective value of the current flowing through the transformer is reduced, the current capacity between the circuit element of the pulse generation unit and the transformer may be small. Therefore, the capacitive load driving device according to the present invention can be easily downsized. In addition, the iron loss is reduced by downsizing the transformer. Thus, power consumption is further reduced.
In addition, the breakdown voltage of the switch part of the power recovery part is reduced. As a result, in the above-described capacitive load driving device according to the present invention, the circuit element is easily reduced in size, so that the mounting area is easily reduced.

The capacitive load driving device according to the present invention may include a first driving unit and a second driving unit each having a pulse generation unit and a transformer.
At that time, the connection between the secondary windings of the two transformers and the capacitive load may be either in series or in parallel. In any connection, the power required for charging and discharging the capacitive load is supplied to the capacitive load through both of the two pulse generators. In particular, the current flowing through each of the two pulse generators can be kept small. Therefore, each circuit element of the two pulse generators may have a small current capacity. As a result, the capacitive load driving device according to the present invention can be easily downsized.
Further, when the connection between the two transformers and the capacitive load is in series, the secondary voltage of each of the two transformers is relatively low. Therefore, the withstand voltage of the transformer may be low. In addition, the primary current is reduced for a constant primary voltage. Therefore, the current capacity of the circuit element of the pulse generator can be further reduced. As a result, the capacitive load driving device according to the present invention can be further reduced in size.

According to the first aspect of the present invention, the transformers included in the first and second drive units each include an exciting inductance that resonates with the capacitive load.
On the other hand, according to the second or third aspect of the present invention, at least the first drive unit includes the auxiliary inductor or the power recovery unit. Thus, the special circuit element for resonating with the capacitive load may be installed in at least one of the two driving units. Of course, in addition to the first drive unit, the second drive unit may also include the auxiliary inductor or the power recovery unit.

The capacitive load driving device according to the present invention may include a control unit that maintains the switching operation of the first driving unit and the switching operation of the second driving unit in the same phase or in opposite phase. Here, the polarity of the phase is determined according to the polarity of each transformer so that the polarities of the pulse voltages applied to the capacitive load are aligned.
According to the first aspect of the present invention, the exciting inductances of the transformers included in the first and second drive units simultaneously resonate with the capacitive load.
According to the second or third aspect of the present invention, when both the first and second drive units include an auxiliary inductor or a power recovery unit, the auxiliary inductor or the power recovery unit is simultaneously a capacitive load. Resonates.
These resonances effectively reduce reactive power due to charging and discharging of the capacitive load.

The capacitive load driving device according to the present invention additionally includes a switching operation of the first driving unit and a switching operation of the second driving unit when the secondary winding of the transformer is connected in series with the capacitive load. A control unit that sets the phase difference between the two to a range larger than 0 ° and smaller than 180 °. Here, the phase of any switching operation of the first and second drive units may be used as a reference.
According to the first aspect of the present invention, the excitation inductances of the transformers included in the first and second drive units alternately resonate with the capacitive load.
According to the second or third aspect of the present invention, when each of the first and second drive units includes an auxiliary inductor or a power recovery unit, the auxiliary inductor or the power recovery unit alternately and independently has a capacity. Resonates with the sexual load.
Even at those resonances, reactive power due to charging and discharging of the capacitive load is reduced.
According to the second or third aspect of the present invention, the second drive unit may not include the auxiliary inductor or the power recovery unit.
According to the third aspect of the present invention, in addition, the switch unit of the power recovery unit may only flow the current accompanying the resonance between the inductor and the capacitive load in one direction.
As a result, the number of parts is further reduced and the mounting area is reduced.

In the above capacitive load driving device according to the present invention, preferably, the switching element of the pulse generation unit is a wide gap semiconductor switching element. Here, the wide band gap semiconductor includes, for example, silicon carbide (SiC), diamond, gallium nitride (GaN), or zinc oxide (ZnO).
The wide bandgap semiconductor switch element has a smaller increase in on-resistance with a rise in breakdown voltage than the conventional silicon semiconductor switch element. That is, the wide band gap semiconductor switch element has a high breakdown voltage and a low on-resistance. Therefore, it is extremely suitable for use as a switching element of the pulse generator. In particular, when the capacitive load is a PDP, a large current (although instantaneously) flows through the pulse generator due to the application of a high voltage to the PDP. Therefore, the use of the wide bandgap semiconductor switch element is extremely effective in achieving both a reduction in the size of the device due to a high breakdown voltage and a reduction in conduction loss due to a decrease in on-resistance.

In the above capacitive load driving device according to the present invention, preferably,
The pulse generator includes a high-side switch element and a low-side switch element as the switch elements, and the high-side switch element and the low-side switch element are connected in series;
A primary winding of the transformer is connected to a connection point between the high-side switch element and the low-side switch element. That is, the pulse generator is a full bridge type or half bridge type inverter. In that case, the breakdown voltage of the switch element is lower than that of the push-pull inverter.

In the capacitive load driving device according to the present invention, preferably, the pulse generator regenerates power to the DC voltage supply source by switching of the switch element. Here, the DC voltage supply source corresponds to, for example, a rectifying unit in the plasma display described above.
For example, when the pulse generator includes the above-described high-side switch element and low-side switch element, any one of the switch elements may be turned on at the end of application of the pulse voltage, and the regenerative current may be passed to the DC voltage supply source.
In the case of the first or second aspect of the present invention, when the application of a series of pulse voltages to the capacitive load ends, for example, at the end of the discharge sustain period in the plasma display, the transformer excitation inductance or Current flows through the auxiliary inductor. That is, at that time, resonance energy remains accumulated in those inductors. The above-described capacitive load driving device according to the present invention regenerates the remaining resonance energy in a DC voltage supply source. Accordingly, the reactive power is further reduced, and the efficiency is further improved.

  The above capacitive load driving device according to the present invention has a transformer on the output side of the pulse generator. Therefore, unlike the conventional driving device, a DC-DC converter may not be included on the input side of the pulse generation unit. Thereby, the capacitive load driving device according to the present invention has a small number of parts and a small mounting area. Furthermore, since power loss due to the DC-DC converter is eliminated, power consumption is low. In addition, as a result of the high voltage from the external power supply being directly applied to the pulse generator, the current capacity of the circuit element may be smaller than the conventional current capacity, so that the entire drive device can be easily downsized.

According to the first or second aspect of the present invention, the exciting inductance or auxiliary inductor of the transformer resonates with the capacitive load. The resonance reduces reactive power resulting from charging and discharging of the capacitive load. In particular, unlike a conventional drive device, an inductor (transformer excitation inductance or auxiliary inductor) that resonates with a capacitive load is in parallel with the secondary winding of the transformer.
Especially when the capacitive load is a PDP, the above resonance does not adversely affect the image of the PDP. In addition, since the ringing associated with the resonance does not have to be taken into consideration when the PDP emits light, the withstand voltage of the circuit element of the capacitive load driving device may be low.
As a result, according to the first and second aspects of the present invention, the power recovery unit may not be included. Accordingly, the capacitive load driving device according to the present invention has a smaller number of components and a smaller mounting area than the conventional driving device. Therefore, it is easy to reduce the size of the entire drive device.

Further according to the first or second aspect of the present invention, when the transformer exciting inductance or auxiliary inductor begins to resonate with the capacitive load, current is already flowing through the exciting inductance or auxiliary inductor. Therefore, the rise and fall of the pulse voltage is faster than those in the conventional driving device. As a result, the maximum number of pulses that can be applied to the capacitive load for a certain period of time is more easily increased than the maximum number of pulses in a conventional drive device.
In particular, when the capacitive load is a PDP, the subfield, particularly its discharge sustaining period, is shortened by shortening the rising and falling periods of the pulse voltage. Therefore, the number of subfields per field increases easily. Thus, when the above-described capacitive load driving device according to the present invention is mounted on a plasma display as a PDP driving device, it is easy to further refine the gradation of the PDP, that is, further improve the image quality.

  According to the third aspect of the present invention, the inductor of the power recovery unit resonates with the capacitive load. Further, the resonance period is surely limited to a desired period by turning on and off the switch section. In other words, no current flows through the inductor of the power recovery unit except during the resonance period. Thus, the power loss is particularly small among the means of power recovery.

When the power recovery unit is connected to the secondary winding of the transformer, the current due to resonance between the inductor of the power recovery unit and the capacitive load is further applied to the secondary winding of the transformer, unlike the conventional driving device. Is not really upstream. Therefore, no copper loss occurs in the transformer during the resonance period. As a result, power consumption is reduced.
In addition, since the effective value of the current flowing through the transformer is reduced, the current capacity between the circuit element of the pulse generation unit and the transformer may be small. Therefore, the capacitive load driving device according to the present invention can be easily downsized. In particular, the iron loss is reduced by downsizing the transformer. As a result, power consumption is further reduced. In addition, since the breakdown voltage of the switch portion of the power recovery unit is reduced, the power recovery unit can be easily downsized and the mounting area can be easily reduced.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of the invention will be described with reference to the drawings.
Embodiment 1
FIG. 1 is a block diagram showing a configuration of a plasma display according to Embodiment 1 of the present invention. The plasma display includes a PDP 20, a PFC converter 40, a PDP driving device 10, and a control unit 30.

The PDP 20 is preferably an AC type and has a three-electrode surface discharge type structure. Address electrodes (not shown) are arranged on the rear substrate of the PDP 20 in the vertical direction of the panel. On the front substrate of PDP 20, sustain electrodes X1, X2, X3,... And scan electrodes Y1, Y2, Y3,... Are alternately arranged in the horizontal direction of the panel. Since the sustain electrodes X1, X2, X3,... Are connected to each other, the potentials are substantially equal. The address electrodes and the scan electrodes Y1, Y2, Y3,... Can be individually changed in potential.
Discharge cells (not shown) are installed at intersections between the pair of sustain electrodes and scan electrodes adjacent to each other and the address electrodes. When a predetermined pulse voltage is applied between the sustain electrode, the scan electrode, and the address electrode, a discharge is generated in the discharge cell located at the intersection. As a result, the discharge cell emits light.

  Preferably, the ADS method is adopted as the display method of the PDP 20. In the ADS system, one field of an image (for example, 1/60 second (= about 16.7 msec) interval in Japanese television broadcasting) is divided into a plurality of (for example, 8 to 12) subfields. In each subfield, an initialization period, an address period, and a discharge sustain period are set in common for all the discharge cells of the PDP 20.

In the initialization period, an initialization pulse voltage is applied between the sustain electrodes X1, X2, X3,... And the scan electrodes Y1, Y2, Y3,. Thereby, wall charges are made uniform in all the discharge cells.
In the address period, the scan pulse voltage is sequentially applied to the scan electrodes Y1, Y2, Y3,. At the same time, a signal pulse voltage is applied to some of the address electrodes. Here, the address electrode to which the signal pulse voltage is to be applied is selected based on the video signal input from the outside. Discharge occurs in the discharge cell located at the intersection of the scan electrode to which the scan pulse voltage is applied and the address electrode to which the signal pulse voltage is applied, and wall charges are accumulated.
In the discharge sustain period, the discharge sustain pulse voltage is simultaneously and periodically applied between the sustain electrodes X1, X2, X3,... And the scan electrodes Y1, Y2, Y3,. At that time, in the discharge cell in which the wall charges are accumulated during the address period, the gas discharge is maintained and light emission occurs. Since the length of the discharge sustaining period is different for each subfield, the light emission time per field of the discharge cell, that is, the luminance of the discharge cell is adjusted by selecting the subfield to emit light.

The PFC converter 40 is connected to an external commercial AC power source AC. The PFC converter 40 receives AC power (general effective voltage 85 to 265 V) from the commercial AC power supply AC, and converts the AC power into DC power (for example, an average voltage Vs of about 400 V). Further, the PFC converter 40 keeps the power factor substantially equal to 1 for the input from the commercial AC power supply AC by its switching operation.
The plasma display may have a full-wave rectification type AC-DC converter that does not improve the power factor in place of the PFC converter 40. In addition, a full-wave rectifier circuit including a diode bridge and a capacitor may be provided.

The PDP driving device 10 includes a sustaining pulse generator 1, a transformer 2, an inductor L, an initialization / scanning pulse generator 3, and an address electrode driver (not shown).
An input terminal of the sustaining pulse generator 1 is connected to the PFC converter 40, and an output terminal is connected to both ends of the primary winding 2a of the transformer 2.
Discharge sustaining pulse generator 1 includes a switching inverter, and generates primary pulse voltage VF using DC power input from PFC converter 40.

One end of the secondary winding 2b of the transformer 2 is connected to the initialization / scanning pulse generator 3, and the other end is grounded. In that case, the sustain electrodes X1, X2, X3,... Of the PDP 20 are grounded. For example, a PDP 20 frame (not shown) is used as the ground conductor. In FIG. 1, the secondary-side ground terminal of the transformer 2 is indicated by a symbol different from the ground terminal of the primary-side high-voltage portion (portion surrounded by a broken line shown in FIG. 1). The sustain electrodes X1, X2, X3,... Are connected to the secondary winding 2b of the transformer 2 through the ground conductor (the frame of the PDP 20). In addition, the sustain electrodes X1, X2, X3,... May be directly connected to the secondary winding 2b of the transformer 2 with conductive wires.
The transformer 2 converts the primary pulse voltage VF into a secondary pulse voltage having a predetermined level (for example, about 175 V), that is, a discharge sustaining pulse voltage Vp. The sustaining voltage pulse Vp is simultaneously applied between the sustain electrodes X1, X2, X3,... And the scan electrodes Y1, Y2, Y3,.

  The inductor L is connected in parallel with the secondary winding 2b of the transformer 2. Here, the inductor L is preferably an exciting inductance of the transformer 2. In addition, the inductor L may be an element (auxiliary inductor) independent of the transformer 2. In that case, the inductance of the auxiliary inductor L is preferably sufficiently smaller than the exciting inductance of the transformer 2.

The initialization / scanning pulse generator 3 is connected to the scanning electrodes Y1, Y2, Y3,. The initialization / scanning pulse generation unit 3 includes a switching inverter, and applies the initialization pulse voltage and the scanning pulse voltage individually to the scanning electrodes Y1, Y2, Y3,. The initialization / scanning pulse generator 3 further separates the secondary winding 2b of the transformer 2 from the scan electrodes Y1, Y2, Y3,... During the initialization / address period, and the scan electrodes Y1, Y2, Y3 during the discharge sustain period. Connect to ...
As shown in FIG. 1, the sustaining pulse generator 1, the transformer 2, and the initialization / scanning pulse generator 3 are integrated on the same side with respect to the PDP 20. In that case, for example, since the heat / noise source included in the PDP driving apparatus 10 is contained in a relatively narrow range, it is relatively easy to take an effective countermeasure against heat / noise.

  Unlike FIG. 1, one end of the secondary winding 2b of the transformer 2 may be connected to the sustain electrodes X1, X2, X3,... Of the PDP 20 through a separation switch, and the other end may be grounded. In that case, the separation switch connects the sustain electrodes X1, X2, X3,... To the secondary winding 2b of the transformer 2 during the discharge sustaining period and separates it from the secondary winding 2b of the transformer 2 during the initialization / addressing period. To ground. On the other hand, the initialization / scanning pulse generator 3 grounds the scan electrodes Y1, Y2, Y3,... During the discharge sustain period.

  The control unit 30 controls switching of each of the sustaining pulse generating unit 1, the initialization / scanning pulse generating unit 3, and the address electrode driving unit (not shown) according to the ADS method. In particular, the control unit 30 determines an address electrode and a subfield to which the signal pulse voltage is applied based on the video signal. As a result, an image corresponding to the image signal is reproduced on the PDP 20.

  FIG. 2 is an equivalent circuit diagram of the sustaining pulse generator 1, the transformer 2, the inductor L, and the PDP 20. 3 and 4 are equivalent circuit diagrams of the initialization / scanning pulse generation unit 3. FIG. Here, the equivalent circuit of the PDP 20 is represented only by the sustain electrode X, the scan electrode Y, and the capacitance between these electrodes X and Y, that is, the panel capacitance Cp. The path of current flowing through the PDP 20 during discharge in the discharge cell is omitted.

Discharge sustaining pulse generator 1 is a full-bridge inverter, and includes four main switch elements Q1 to Q4 (see FIG. 2). These main switch elements Q1 to Q4 are preferably MOSFETs, and more preferably wide band gap semiconductor switch elements. Here, the wide band gap semiconductor includes, for example, SiC, diamond, GaN, or ZnO. Wide band gap semiconductor switch elements have particularly high breakdown voltage and low on-resistance.
When the sustaining pulse voltage is applied, a large current flows through the main switch elements Q1 to Q4 of the sustaining pulse generator 1 due to the discharge of the PDP 20 and the charging / discharging of the panel capacitance Cp. Therefore, the use of a wide bandgap semiconductor switching element is extremely effective in achieving both the reduction in the size of the sustaining pulse generator 1 and the reduction in conduction loss.
In addition, the four main switch elements Q1 to Q4 may be IGBTs or bipolar transistors.

The DC voltage Vs is applied from the PFC converter 40 to the input terminal 1T of the sustaining pulse generator 1.
A series connection of the first high-side main switch element Q1 and the first low-side main switch element Q2, and a series connection of the second high-side main switch element Q3 and the second low-side main switch element Q4, respectively. Connected between the input terminal 1T and the ground terminal. The primary winding 2a of the transformer 2 is connected between the connection points J1 and J2 of the two series connections.
One end of the secondary winding 2b of the transformer 2 is connected to the scan electrode Y of the PDP 20 through the two terminals 3A and 3B of the initialization / scanning pulse generator 3, and the other end is connected to the sustain electrode X of the PDP 20.
In FIG. 2, the sustain electrode X is grounded. In addition, the scanning electrode Y may be grounded.

  There are two types of connection between the secondary winding 2b of the transformer 2 and the initialization / scanning pulse generator 3 (see FIGS. 3 and 4). The initialization / scanning pulse generation unit 3 includes five constant voltage sources E1 to E5, two switch elements Q5 and Q6, a bidirectional switch unit Q7, and two separate switch elements QS1 and QS2 as common components in both modes. , A blocking diode D, two ramp waveform generators QR1, QR2, a bypass switch element QB, two scan switch elements Q8, Q9, and two auxiliary switch elements Q10, Q11.

Five constant voltage sources E1, E2, E3, E4, and E5 have positive and negative voltages V1, V2, V3, V4, and V5 (for example, about 175V, about 220V, about 25V, and about 240V), respectively. Only about 120V).
The two switch elements Q5 and Q6, the two separation switch elements QS1 and QS2, the bypass switch element QB, the two scan switch elements Q8 and Q9, and the two auxiliary switch elements Q10 and Q11 are preferably MOSFETs.
In particular, the bypass switch element QB is more preferably a wide band gap semiconductor switch element. During the address period, a large current generally flows through the bypass switch element QB (see FIG. 5). Therefore, the use of a wide bandgap semiconductor switch element is extremely effective in achieving both reduction in size of the bypass switch element QB and reduction in conduction loss. In addition, the bypass switch element QB may be an IGBT or a bipolar transistor.
These switch elements Q5, Q6, QS1, QS2, QB, Q8, Q9, Q10, Q11 all have body diodes in parallel, and thus have polarity. Hereinafter, the terminal of the switch element corresponding to the anode (or cathode) of the body diode is referred to as the anode (or cathode).

  The bidirectional switch part Q7 includes two switch elements, which are preferably MOSFETs. In addition, an IGBT or a bipolar transistor may be used. Each of the two switch elements has a polarity because it includes a body diode in parallel. The anodes of the two switch elements are connected to each other and their on / off states are always controlled equally.

  Ramp waveform generators QR1 and QR2 preferably include N-channel MOSFETs (NMOS). Each NMOS is more preferably a wide bandgap semiconductor switch element. During the initialization period, a large current flows through the ramp waveform generators QR1 and QR2 (see FIG. 5). Therefore, the use of a wide bandgap semiconductor switch element is extremely effective in achieving both reduction in the size of the ramp waveform generators QR1 and QR2 and reduction in conduction loss. The gate and drain of each NMOS are connected by a capacitor. When the ramp waveform generators QR1 and QR2 are turned on, the voltage at both ends changes to zero at a substantially constant speed as the capacitors are charged. Since each NMOS includes a body diode in parallel, each of the ramp waveform generators QR1 and QR2 has a polarity.

The negative electrode of the first constant voltage source E1 is grounded, and the positive electrode is connected to the cathode of the high side switch element Q5. The anode of the high side switch element Q5 is connected to the cathode of the low side switch element Q6. The anode of the low side switch element Q6 is grounded.
A connection point J3 between the high-side switch element Q5 and the low-side switch element Q6 is connected to the anode of the first separation switch element QS1. The cathode of the first separation switch element QS1 is connected to the cathode of the second separation switch element QS2. The anode of the second separation switch element QS2 is connected to the anode of the low-side scan switch element Q9 (through the second separation switch section QS4 or directly).

The negative electrode of the second constant voltage source E2 is connected to the anode of the first separation switch element QS1, and the positive electrode is connected to the anode of the blocking diode D. The cathode of the blocking diode D is connected to the cathode of the high side ramp waveform generator QR1. The anode of the high side ramp waveform generator QR1 is connected to the cathode of the first separation switch element QS1.
The negative electrode of the third constant voltage source E3 is grounded, and the positive electrode is connected to the anode of the first separation switch element QS1 through the bidirectional switch part Q7.

  The positive electrode of the fourth constant voltage source E4 is grounded, and the negative electrode is connected to the anode of the low side ramp waveform generator QR2 and the anode of the bypass switch element QB. The cathode of the low-side ramp waveform generator QR2 and the cathode of the bypass switch element QB are connected to the anode of the second separation switch element QS2.

The negative electrode of the fifth constant voltage source E5 is connected to the anode of the second separation switch element QS2, and the positive electrode is connected to the cathode of the high side auxiliary switch element Q10. The anode of the high side auxiliary switch element Q10 is connected to the cathode of the high side scan switch element Q8 and the cathode of the low side auxiliary switch element Q11. The anode of the low side auxiliary switch element Q11 is connected to the anode of the low side scan switch element Q9.
The anode of the high side scan switch element Q8 is connected to the cathode of the low side scan switch element Q9. These connection points J4 are connected to one of the scanning electrodes Y of the PDP 20 through the output terminal 3B (see FIG. 2). Here, the series connection of the two scanning switch elements Q8 and Q9 is actually provided in the same number as the plurality of scanning electrodes Y1, Y2,... Connected one by one.

  The installation of the two auxiliary switch elements Q10 and Q11 aims to prevent overvoltage with respect to the two scan switch elements Q8 and Q9. Thereby, malfunction of the two scanning switch elements Q8 and Q9 is avoided. When there is little risk of malfunction, the auxiliary switch elements Q10 and Q11 need not be installed. In this case, the positive electrode of the fifth constant voltage source E5 and the cathode of the high side scan switch element Q8 are short-circuited, and the cathode of the high side scan switch element Q8 and the anode of the low side scan switch element Q9 are separated.

In the connection between the secondary winding 2b of the transformer 2 and the initialization / scanning pulse generation unit 3 according to the first embodiment, the initialization / scanning pulse generation unit 3 includes two separation switch units QS3 and QS4 (see FIG. 3).
The first separation switch unit QS3 is inserted between the input terminal 3A of the initialization / scanning pulse generation unit 3 and the anode of the low-side scanning switch element Q9.
The second separation switch unit QS4 is inserted between the anode of the second separation switch element QS2 and the anode of the low side scan switch element Q9.
The two separation switch sections QS3 and QS4 are both bidirectional switches and include two switch elements. These switch elements are preferably MOSFETs. In addition, an IGBT or a bipolar transistor may be used. Each of the two switch elements has a polarity because it includes a body diode in parallel. The anodes of the two switch elements are connected to each other and their on / off states are always controlled equally.
In the first aspect, more preferably, the second separation switch element QS2, the high-side auxiliary switch element Q10, the switch element on the input terminal 3A side included in the first separation switch part QS3, and the second separation switch part QS4 The switch element on the low-side scanning switch element Q9 side included in the is a wide band gap semiconductor switch element. This is because these switch elements are particularly required to have a high breakdown voltage and a low on-resistance.

In the connection between the secondary winding 2b of the transformer 2 and the initialization / scanning pulse generator 3 according to the second mode, the initialization / scanning pulse generator 3 includes a third separation switch element QS5 (see FIG. 4). .
The third isolation switch element QS5 is preferably a MOSFET. In addition, an IGBT or a bipolar transistor may be used. Since this switch element includes a body diode in parallel, it has polarity.
The anode of the third separation switch element QS5 is connected to the input terminal 3A of the initialization / scanning pulse generator 3, and the cathode is connected to the connection point J3 of the two switch elements Q5 and Q6.

  FIG. 5 shows the potential of the scan electrode Y of the PDP 20 in the initialization period, the address period, and the discharge sustain period, and the switch parts Q5, Q6, Q7, Q8, Q9 included in the initialization / scanning pulse generation part 3. FIG. 6 is a waveform diagram showing ON periods of main switch elements Q1 to Q4 included in Q10, Q11, QR1, QR2, QB, QS1, QS2, QS3, QS4, QS5, and discharge sustaining pulse generator 1. In FIG. 5, the ON period of each switch part is indicated by a hatched part.

During the initialization period, in the first mode, the first separation switch unit QS3 maintains the off state, and the second separation switch unit QS4 maintains the on state. In the second embodiment, the third separation switch element QS5 maintains the off state. As a result, the secondary winding 2b of the transformer 2 is separated from the scan electrode Y, and the initialization / scan pulse generator 3 is connected to the scan electrode Y.
At that time, the potential of the scan electrode Y changes due to the application of the initialization pulse voltage. The potential change is divided into the following five modes I to V.

<Mode I>
The low-side switch element Q6, the low-side scan switch element Q9, the low-side auxiliary switch element Q11, the two separation switch elements QS1 and QS2, and the second separation switch section QS4 are kept on (the remaining switch elements are kept off) To do). As a result, the scan electrode Y is maintained at the ground potential (≈0).
<Mode II>
The low side switch element Q6 is turned off and the high side switch element Q5 is turned on (the state of the remaining switch elements is maintained as it is). As a result, the potential of the scan electrode Y rises from the ground potential (≈0) by the voltage V1 of the first constant voltage source E1.

<Mode III>
The first separation switch element QS1 is turned off, and the high side ramp waveform generator QR1 is turned on (the state of the remaining switch elements is maintained as it is). As a result, the potential of the scan electrode Y rises from the potential V1 in mode II by the voltage V2 of the second constant voltage source E2 at a constant speed.
In this way, the applied voltage uniformly increases in all discharge cells of the PDP 20 to the upper limit V1 + V2 of the initialization pulse voltage relatively slowly. Thereby, uniform wall charges are accumulated in all the discharge cells of the PDP 20. At that time, since the increasing rate of the applied voltage is small, the light emission of the discharge cell is suppressed to be weak.

<Mode IV>
The high-side switch element Q5 is turned off, and the bidirectional switch unit Q7 and the first separation switch element QS1 are turned on (the state of the remaining switch elements is maintained as it is). As a result, the potential of the scan electrode Y suddenly drops from the upper limit V1 + V2 of the sustaining voltage pulse to a potential that is higher than the ground potential by the voltage V3 of the third constant voltage source E3.
<Mode V>
The bidirectional switch part Q7 and the second separation switch element QS2 are turned off, and the low-side ramp waveform generating part QR2 is turned on (the state of the remaining switch elements is maintained as it is). As a result, the potential of the scan electrode Y drops from the potential V3 in mode IV to the potential −V4 that is lower than the ground potential by the voltage V4 of the fourth constant voltage source E4 at a constant speed.
In this way, a voltage having a polarity opposite to that applied in modes II to IV is uniformly applied to all discharge cells of PDP 20. In particular, the applied voltage drops relatively slowly. Thereby, wall charges are uniformly removed and uniformed in all the discharge cells. At that time, since the rate of drop of the applied voltage is small, the light emission of the discharge cell is suppressed to be weak.

During the address period, in the first mode, the first separation switch unit QS3 maintains the off state, and the second separation switch unit QS4 maintains the on state. In the second embodiment, the third separation switch element QS5 maintains the off state. As a result, the secondary winding 2b of the transformer 2 is separated from the scan electrode Y.
Further, the bypass switch element QB is kept on. Accordingly, the anode of the low-side scan switch element Q9 is maintained at a potential −V4 (hereinafter referred to as the lower limit of the scan pulse voltage) that is lower than the ground potential by the voltage V4 of the fourth constant voltage source E4.
On the other hand, the high side auxiliary switch element Q10 maintains the on state, and the low side auxiliary switch element Q11 maintains the off state. As a result, the cathode of the high-side scan switch element Q8 is maintained at a potential −V4 + V5 (hereinafter referred to as the upper limit of the scan pulse voltage) that is higher than the lower limit −V4 of the scan pulse voltage by the voltage V5 of the fifth constant voltage source E5. .

  At the start of the address period, for all the scan electrodes Y1, Y2, Y3,... (See FIG. 1), the high side scan switch element Q8 is kept on and the low side scan switch element Q9 is kept off. Accordingly, the potentials of all the scan electrodes Y are uniformly maintained at the upper limit −V4 + V5 of the scan pulse voltage.

Subsequently, the initialization / scanning pulse generating unit 3 sequentially changes the potentials of the scanning electrodes Y1, Y2, Y3,... As follows (see the scanning pulse voltage SP shown in FIG. 5).
When one of the scan electrodes Y is selected, the high side scan switch element Q8 connected to the scan electrode Y is turned off and the low side scan switch element Q9 is turned on. As a result, the potential of the scan electrode Y drops to the lower limit −V4 of the scan pulse voltage.
After a predetermined time has elapsed, the low side scan switch element Q9 connected to the scan electrode Y is turned off, and the high side scan switch element Q8 is turned on. As a result, the potential of the scan electrode Y returns to the upper limit −V4 + V5 of the scan pulse voltage.
The scan switch element pairs Q8 and Q9 connected to the scan electrodes Y1, Y2, Y3,... Sequentially perform the same switching operation. Thus, the scan pulse voltage SP is sequentially applied to each of the scan electrodes Y1, Y2, Y3,.

  At the same time as the scan pulse voltage is applied to one of the scan electrodes, a signal pulse voltage is applied to one of the address electrodes. At that time, the voltage between the scan electrode and the address electrode is higher than the voltage between the other electrodes. Therefore, discharge occurs in the discharge cell located at the intersection between the scan electrode and the address electrode, and new wall charges are accumulated on the surface.

  During the discharge maintaining period, in the first mode, the first separation switch unit QS3 maintains the on state, and the second separation switch unit QS4 maintains the off state. In the second embodiment, the first, second, and third separation switch elements QS1, QS2, and QS5 maintain the on state. Further, in the initialization / scanning pulse generation unit 3, the low-side scan switch element Q9 and the low-side auxiliary switch element Q11 are kept on, and the remaining switch elements are kept off. Thereby, the secondary winding 2b of the transformer 2 is connected to the scan electrode Y. On the other hand, the initialization / scanning pulse generation unit 3 substantially stops.

In the discharge sustain period, the discharge sustain pulse generator 1 applies the discharge sustain pulse voltage Vp between the scan electrode Y and the sustain electrode X as follows (see FIG. 2). At that time, since discharge is maintained in the discharge cells in which wall charges are accumulated during the address period, light emission occurs.
At the start of the discharge sustain period, the first high-side main switch element Q1 and the second low-side main switch element Q4 are turned on. Thereby, the primary pulse voltage VF is applied to the primary winding 2a of the transformer 2, and a secondary pulse voltage is induced in the secondary winding 2b of the transformer 2. At that time, the inductor L and the panel capacitance Cp resonate. Accordingly, the potential of the scan electrode Y, that is, the sustaining voltage pulse Vp increases.

Until a predetermined time corresponding to the pulse width of the sustaining voltage pulse has elapsed, the control unit 30 maintains the first high-side main switch element Q1 and the second low-side main switch element Q4 in the on state, The switch elements Q2 and Q3 are maintained in the off state. At that time, the sustaining voltage pulse Vp is maintained at a positive peak value (see FIG. 5). The peak value is determined by the potential Vs of the input terminal 1T of the sustaining pulse generator 1 and the winding ratio of the transformer 2.
When the discharge is maintained in the discharge cell of the PDP 20, electric power for maintaining the discharge current is supplied to the discharge cell through the input terminal 1T.
On the other hand, since the voltage Vp across the inductor L is maintained at a constant value, the current IL flowing through the inductor L increases linearly in the direction of the arrow shown in FIG.

When the predetermined time elapses, the control unit 30 turns off the first high-side main switch element Q1 and the second low-side main switch element Q4 (see FIG. 5). At that time, resonance occurs between the inductor L and the panel capacitance Cp.
At the start of the resonance, the current IL flowing through the inductor L quickly discharges the panel capacitance Cp and further charges with the opposite polarity. Along with this, the sustaining voltage pulse Vp quickly decreases, and its polarity quickly changes from positive to negative (see FIG. 5).

When the sustaining voltage pulse Vp reaches a negative peak value, the control unit 30 turns on the first low-side main switch element Q2 and the second high-side main switch element Q3. At that time, since the voltage across the first low-side main switch element Q2 and the second high-side main switch element Q3 is substantially equal to zero, no switching loss occurs. By the switching, the sustaining voltage pulse Vp is maintained at a negative peak value.
When the discharge is maintained in the discharge cell of the PDP 20, electric power for maintaining the discharge current is supplied to the discharge cell through the input terminal 1T.
On the other hand, since the voltage Vp across the inductor L is maintained at a constant value, the current IL flowing through the inductor L increases linearly in the direction opposite to the arrow shown in FIG.

When this state is maintained for the predetermined time, the control unit 30 turns off the first low-side main switch element Q2 and the second high-side main switch element Q3. At that time, resonance occurs between the inductor L and the panel capacitance Cp.
At the start of the resonance, the current IL flowing through the inductor L quickly discharges the panel capacitance Cp and further charges with the opposite polarity. Along with this, the sustaining voltage pulse Vp rises rapidly, and its polarity quickly changes from negative to positive.

During the discharge sustain period, the control unit 30 repeats the above-described on / off control for the main switch elements Q1 to Q4. As a result, the polarity of the sustaining voltage pulse Vp is repeatedly inverted as described above.
In particular, during the rising / falling period of the sustaining voltage pulse Vp, the inductor L resonates with the panel capacitance Cp as described above. The resonance inverts the polarity of the sustaining voltage pulse Vp quickly and smoothly. At that time, almost no power is consumed, and is exchanged between the inductor L and the panel capacitance Cp. That is, during the resonance period, the power consumed by the main switch elements Q1 to Q4, the sustain electrodes X and the scan electrodes Y of the PDP 20, and the resistances (not shown) of the lead wires are suppressed. Thus, the reactive power due to charging / discharging of the panel capacitance Cp is reduced during the discharge sustain period.

At the end of the discharge sustain period, the control unit 30 detects two main switch elements (for example, the first low-side main switch) that have been in the ON state until the end of the last discharge sustain pulse voltage Vp (for example, negative pulse). The element Q2 and the second high-side main switch element Q3) are turned off. At that time, resonance occurs between the inductor L and the panel capacitance Cp.
At the start of the resonance, the current IL flowing through the inductor L quickly discharges the panel capacitance Cp. Along with this, the potential of the scan electrode Y (discharge sustaining pulse voltage Vp) rises rapidly.
When the sustaining voltage pulse Vp reaches a positive peak value, the control unit 30 turns on the first high-side main switch element Q1 and the second low-side main switch element Q4 (see section VI shown in FIG. 5). . At this time, a regenerative current to the input terminal 1T flows through the primary winding 2a of the transformer 2 due to the current IL flowing through the inductor L.
Immediately before the current IL flowing through the inductor L is attenuated to substantially zero, the control unit 30 turns off the first high-side switch element Q1 and the second low-side switch element Q4. Thereby, all the energy remaining in the inductor L is regenerated in the PFC converter 40.
The applied voltage in the regeneration period immediately after the discharge maintaining period, that is, the period VI in which the potential of the scan electrode Y is maintained high is preferably used as part of the initialization pulse voltage in the next initialization period.
Thus, dissipation of energy remaining in the inductor L at the end of the discharge sustain period is avoided. Therefore, the efficiency related to the application of the sustaining voltage pulse is improved.

  Apart from the above, the controller 30 may maintain both the first high-side switch element Q1 and the second low-side switch element Q4 in the off state at the end of the discharge sustain period. Since the discharge current is cut off during the off period, no new wall charges are accumulated in the discharge cells of the PDP 20. Therefore, the transition to the next initialization period is smooth. Preferably, the voltage change in the off period is used as a part of the initialization pulse voltage in the next initialization period.

As described above, the PDP driving apparatus 10 according to the first embodiment of the present invention has the transformer 2 on the output side of the sustaining pulse generator 1. The transformer 2 appropriately adjusts the level of the sustaining voltage pulse Vp and applies it between the sustaining electrode X and the scanning electrode Y of the PDP 20. Therefore, the PDP driving device 10 does not have to include a DC-DC converter on the input side of the sustaining pulse generating unit 1. As a result, the PDP driving device 10 has a small number of components and a small mounting area.
Furthermore, since power loss due to the DC-DC converter is eliminated, power consumption is low.
In addition, the high voltage Vs sent from the PFC converter 40 is directly applied to the sustaining pulse generator 1. At that time, the current in the sustaining pulse generator 1 is small. Therefore, the current capacity of the circuit element may be small. As a result, the sustaining pulse generator 1 can be easily downsized.
The transformer 2 further insulates between the high voltage portion on the primary side (the portion surrounded by the broken line shown in FIG. 1) and the PDP 20 on the secondary side. Thereby, the PDP driving device 10 sufficiently secures safety.

In the PDP driving apparatus 10 according to the first embodiment of the present invention, the inductor L (the exciting inductance of the transformer 2 or the auxiliary inductor) is set to the panel capacitance Cp of the PDP 20 as described above during the rising period and the falling period of the sustaining voltage pulse Vp. Resonates. The resonance inverts the polarity of the voltage Vp across the panel capacitance Cp with almost no power consumption. That is, during the resonance period, the power consumed by the circuit elements of the discharge sustain pulse generator 1, the sustain electrodes and the scan electrodes of the PDP 20, and the resistances of the lead wires is suppressed. Thus, the reactive power due to charging / discharging of the panel capacitance Cp of the PDP 20 is reduced.
Furthermore, since the inductor L is connected in parallel with the secondary winding 2b of the transformer 2, the above-described resonance period is limited to the rising period and the falling period of the sustaining voltage pulse Vp. Therefore, the above resonance does not adversely affect the image of the PDP 20. In addition, since the ringing associated with the resonance does not have to be taken into consideration when the PDP 20 emits light, the withstand voltage of the circuit elements of the PDP driving device 10 may be low.
As a result, in the PDP driving apparatus 10 according to Embodiment 1 of the present invention, the sustaining pulse generation unit 1 does not have to include the power recovery unit. As a result, the PDP driving device 10 has a smaller number of parts and a smaller mounting area.

When the exciting inductance of the transformer 2 is used as the inductor L, a dedicated component is not necessary as a means for collecting power. Therefore, the PDP driving device 10 has a smaller number of parts and a small mounting area.
When an auxiliary inductor is used as the inductor L and its inductance is set to be sufficiently smaller than the exciting inductance of the transformer 2, the resonance current mainly flows through the auxiliary inductor and hardly flows through the transformer 2. Therefore, since the copper loss of the transformer 2 is reduced, the PDP driving device 10 has low power consumption.

When the inductor L (excitation inductance or auxiliary inductor of the transformer 2) starts to resonate with the panel capacitance Cp of the PDP 20, a current is already flowing through the inductor L. Therefore, the rise / fall of the sustaining voltage pulse Vp is fast. That is, the rising period and the falling period of the discharge sustaining pulse voltage Vp are shortened. As a result, since the discharge sustain period is shortened, the number of subfields per field is easily increased.
Thus, in the plasma display according to Embodiment 1 of the present invention, it is easy to further refine the gradation of the PDP 20, that is, further improve the image quality.

  The sustaining pulse generator 1 according to the first embodiment of the present invention includes a full-bridge inverter as shown in FIG. In addition, the discharge sustaining pulse generation unit may include a half-bridge inverter (one in which one of the two main switch elements is connected in series (for example, Q3 and Q4) is replaced with a series connection of two capacitors). At that time, the turn ratio of the transformer 2 is preferably set to twice the turn ratio of the transformer 2 included in the full-bridge inverter. As a result, the effective value of the primary voltage VF of the transformer 2 is maintained while the effective values of the output voltage Vs and the sustaining pulse voltage Vp of the PFC converter 40 are maintained substantially equal to the effective values of the full-bridge inverter. Is halved. As a result, since the iron loss of the transformer 2 is reduced, the PDP driving device 10 has low power consumption.

<< Embodiment 2 >>
FIG. 6 is a block diagram showing a configuration of a plasma display according to Embodiment 2 of the present invention. In FIG. 6, the same components as those shown in FIG. 1 are denoted by the same reference numerals as those shown in FIG. Furthermore, the description about Embodiment 1 is used about the detail of those similar components.

The plasma display includes a PFC converter 40, a PDP driving device, a PDP 20, and a control unit 31. The PDP drive device includes a first drive unit 10Y and a second drive unit 10X.
The first driver 10Y includes a first sustaining pulse generator 1Y, a first transformer 2Y, a first inductor LY, and an initialization / scanning pulse generator 3Y.
The second drive unit 10X includes a second sustaining pulse generating unit 1X, a second transformer 2X, a second inductor LX, and an initialization pulse generating unit 3X.
Here, the initialization pulse generator may be included in only one of the first driver 10Y and the second driver 10X.

The input terminal 1T of the first sustaining pulse generator 1Y is connected to the PFC converter 40, and the output terminal is connected to both ends of the primary winding 2aY of the first transformer 2Y. The first sustaining pulse generator 1Y includes a switching inverter and generates a first primary pulse voltage VFY using DC power input from the PFC converter 40.
One end of the secondary winding 2bY of the first transformer 2Y is connected to the initialization / scanning pulse generator 3Y, and the other end is grounded. For example, a PDP 20 frame (not shown) is used as the ground conductor.

The initialization / scanning pulse generator 3Y is connected to the scanning electrodes Y1, Y2, Y3,. The initialization / scanning pulse generator 3Y includes a switching inverter, and individually applies the initialization pulse voltage and the scanning pulse voltage to the scanning electrodes Y1, Y2, Y3,.
The initialization / scanning pulse generator 3Y further separates the secondary winding 2bY of the first transformer 2Y from the scan electrodes Y1, Y2, Y3,... In the initialization / address period, and the scan electrodes Y1, Y2,. Connect to Y2, Y3,.

The input terminal 1T of the second discharge sustaining pulse generator 1X is connected to the PFC converter 40, and the output terminal is connected to both ends of the primary winding 2aX of the second transformer 2X. The second sustaining pulse generator 1X includes a switching inverter, and generates a second primary pulse voltage VFX using DC power input from the PFC converter 40.
One end of the secondary winding 2bX of the second transformer 2X is connected to the initialization pulse generator 3X, and the other end is grounded. As the ground conductor, a ground conductor to which the secondary winding 2bY of the first transformer 2Y is connected, for example, a frame (not shown) of the PDP 20 is used. Thereby, the secondary winding 2bX of the second transformer 2X is connected to the secondary winding 2bY of the first transformer 2Y through its ground conductor (for example, the frame of the PDP 20). In addition, both secondary windings 2bY and 2bX may be directly connected by a conductive wire.

The initialization pulse generator 3X is connected to the sustain electrodes X1, X2, X3,. The initialization pulse generator 3X includes a switching inverter and applies the initialization pulse voltage to the sustain electrodes X1, X2, X3,.
The initialization pulse generator 3X further separates the secondary winding 2bX of the second transformer 2X from the sustain electrodes X1, X2, X3,... In the initialization / address period, and the sustain electrodes X1, X2,. Connect to X3, ...

  The two inductors LY and LX are connected in parallel with the secondary windings 2bY and 2bX of the transformers 2Y and 2X, respectively. Each of the inductors LY and LX is preferably an excitation inductance of the connected transformers 2Y and 2X. In addition, the inductors LY and LX may be elements (auxiliary inductors) independent of the transformers 2Y and 2X. In this case, preferably, the inductance of the auxiliary inductor is sufficiently smaller than the excitation inductance of the transformers 2Y and 2X.

The control unit 31 controls switching of each of the two sustaining pulse generation units 1Y and 1X, the initialization / scanning pulse generation unit 3Y, the initialization pulse generation unit 3X, and the address electrode driving unit (not shown) according to the ADS method. To do. In particular, the control unit 31 synchronizes the two primary pulse voltages VFY and VFX.
The control unit 31 further determines an address electrode and a subfield to which the signal pulse voltage is applied based on the video signal. As a result, an image corresponding to the image signal is reproduced on the PDP 20.

  FIG. 7 is an equivalent circuit diagram of the first drive unit 10Y, the second drive unit 10X, and the PDP 20. Here, the equivalent circuit of the PDP 20 is represented only by the sustain electrode X, the scan electrode Y, and the capacitance between these electrodes X and Y, that is, the panel capacitance Cp, as in FIG. The path of current flowing through the PDP 20 during discharge in the discharge cell is omitted.

The two sustaining pulse generators 1Y and 1X both have the same circuit configuration as the sustaining pulse generator 1 according to the first embodiment, and particularly include a full-bridge inverter (see FIG. 2). In particular, the characteristics of the common circuit elements are substantially equal between the two discharge sustaining pulse generators 1Y and 1X. Similarly, the two transformers 2Y and 2X and the two inductors LY and LX have substantially the same characteristics.
In addition, each discharge sustaining pulse generation unit may include a half-bridge type inverter similarly to the discharge sustaining pulse generation unit according to the first embodiment.

  In FIG. 7, the same reference numerals as those shown in FIG. 2 are given to circuit elements similar to the circuit elements shown in FIG. In particular, for the first drive unit 10Y, a symbol with “Y” added to the end of the symbol shown in FIG. 2 is added, and for the second drive unit 10X, “X” is added to the end of the symbol shown in FIG. The code | symbol which added is attached. Further, the description of the first embodiment is used for details of the similar circuit elements.

  The initialization / scanning pulse generator 3Y has a circuit configuration common to the initialization / scanning pulse generator 3 according to the first embodiment (see FIGS. 3 and 4). Therefore, for the details, FIG. 3, FIG. 4 and the description of Embodiment 1 are incorporated.

The initialization pulse generating unit 3X includes a sixth constant voltage source E6, a high side switch element Q12, a low side switch unit Q13, and a fourth separation switch element QS6.
The sixth constant voltage source E6 maintains the positive electrode potential higher than the negative electrode potential by a constant voltage V6 (for example, about 150 V).
The high side switch element Q12 and the fourth separation switch element QS6 are preferably MOSFETs. In addition, an IGBT or a bipolar transistor may be used. Since these switch elements include body diodes in parallel, they have polarity.
The low side switch part Q13 is a bidirectional switch part, and includes two switch elements. These switch elements are preferably MOSFETs. In addition, an IGBT or a bipolar transistor may be used. Each of the two switch elements has a polarity because it includes a body diode in parallel. The anodes of the two switch elements are connected to each other and their on / off states are always controlled equally.

  FIG. 8 shows potentials of the scan electrode Y and the sustain electrode X of the PDP 20 in the initialization period, the address period, and the discharge sustain period, and the main switch elements Q1Y to Q1Y included in the discharge sustain pulse generators 1Y and 1X. FIG. 6 is a waveform diagram showing ON periods of switch elements Q12, Q13, and QS6 included in Q4Y, Q1X to Q4X, and initialization pulse generator 3X. In FIG. 8, the ON period of each switch element is indicated by a hatched portion.

Through the initialization period and the address period, the fourth separation switch element QS6 maintains the off state. As a result, the secondary winding 2bX of the second transformer 2X is separated from the sustain electrode X of the PDP 20.
At that time, the initialization pulse generator 3X changes the potential of the sustain electrode X by applying the initialization pulse voltage. The potential changes in the following manner according to the potential change of the scan electrode Y.
<Modes I to III>
The high side switch element Q12 maintains the off state, and the low side switch unit Q13 maintains the on state. As a result, the sustain electrode X is maintained at the ground potential (≈0).
<Modes IV to V and address period>
The high side switch element Q12 maintains the on state, and the low side switch unit Q13 maintains the off state. Thereby, the sustain electrode X is maintained at a potential higher than the ground potential by the voltage V6 of the sixth constant voltage source E6.
As described above, when the potential of the sustain electrode X is maintained high in the initialization period modes IV to V and the address period, the third, fourth, and fifth included in the initialization / scanning pulse generation unit 3Y. The voltages V3, V4, V5 of the constant voltage sources E3, E4, E5 are generally set to values different from those in the first embodiment (for example, about 175V, about 90V, about 120V). Accordingly, the voltages between the scan electrode Y and the sustain electrode X in the initialization period modes IV to V and in the address period change in the same manner as the voltage in the first embodiment.

  During the discharge sustain period, the fourth separation switch element QS6 maintains the on state. On the other hand, the high side switch element Q12 and the low side switch part Q13 maintain the off state. Thereby, the secondary winding 2bX of the second transformer 2X is connected to the sustain electrode X of the PDP 20. On the other hand, the initialization pulse generator 3X substantially stops.

The secondary windings 2bY and 2bX of the two transformers 2Y and 2X are connected with their polarities reversed, for example, as shown in FIG. In this case, the control unit 31 maintains the switching operations of the two sustaining pulse generating units 1Y and 1X in substantially the same phase. That is, on / off of the corresponding main switch elements (for example, Q1Y and Q1X) is made to coincide between the two discharge sustain pulse generators 1Y and 1X (see FIG. 8).
The secondary windings 2bY and 2bX of the two transformers 2Y and 2X may be connected with the same polarity separately from the example shown in FIG. In this case, the control unit 31 maintains the switching operations of the two sustaining pulse generating units 1Y and 1X in substantially opposite phases.

The switching operation of the two sustaining pulse generators 1Y and 1X is the same as the switching operation of the sustaining pulse generator 1 according to the first embodiment. Therefore, the potential change of the scan electrode Y of the PDP 20 is maintained in the opposite phase to the potential change of the sustain electrode X. Therefore, the sustaining pulse voltage Vp applied between the scan electrode Y and the sustain electrode X is the same as that according to the first embodiment.
In particular, at the rise / fall of the sustaining voltage pulse Vp, the two inductors LY and LX simultaneously resonate with the panel capacitance Cp of the PDP 20. Due to these resonances, power is efficiently exchanged between the panel capacitance Cp and the two inductors LY and LX. As a result, reactive power due to charging / discharging of the panel capacitance Cp is reduced.

In addition to the above switching control, the control unit 31 may set the following phase difference (greater than 0 ° and smaller than 180 °) between the switching operations of the two sustaining pulse generation units 1Y and 1X ( (See Figure 9).
For example, it is assumed that the secondary windings 2bY and 2bX of the two transformers 2Y and 2X are connected with opposite polarities (see FIG. 7).

  When the first high-side main switch elements Q1Y, Q1X and the second low-side main switch elements Q4Y, Q4Y are kept on in both of the two sustaining pulse generators 1Y, 1X, the potential of the scan electrode Y is The positive peak value Vt is maintained, and the potential of the sustain electrode X is maintained at the negative peak value −Vt (see section A shown in FIG. 9). Accordingly, the sustaining voltage pulse Vp is maintained at the positive peak value 2Vt. Here, the peak value Vt is determined by the potential Vs of the input terminal 1T of the sustaining pulse generators 1Y and 1X and the winding ratio of the transformers 2Y and 2X.

When the state is maintained for a predetermined time corresponding to the pulse width of the sustaining voltage pulse, the control unit 31 performs the first high-side main switch element Q1Y and the second The low side main switch element Q4Y is turned off. At that time, since the current is substantially equal to zero in the first sustaining pulse generator 1Y, no switching loss occurs.
On the other hand, for the second sustaining pulse generator 1X, the on / off states of the four main switch elements Q1X to Q4X are maintained as they are.
Due to the switching, only the inductor LY connected to the first transformer 2Y resonates with the panel capacitance Cp of the PDP 20. As a result, the potential of the scan electrode Y drops from the positive peak value Vt (see section B shown in FIG. 9). Therefore, the sustaining voltage pulse Vp drops from the positive peak value 2Vt.

When the potential of the scan electrode Y reaches the negative peak value −Vt, the sustaining pulse voltage Vp reaches zero. At that time, the controller 31 turns off the first high-side main switch element Q1X and the second low-side main switch element Q4X for the second sustaining pulse generator 1X. Here, since the current is substantially equal to zero in the second sustaining pulse generator 1X, no switching loss occurs.
Subsequently, the control unit 31 turns on the first low-side main switch element Q2Y and the second high-side main switch element Q3Y for the first sustaining pulse generation unit 1Y. On the other hand, for the second sustaining pulse generator 1X, the on / off states of the four main switch elements Q1X to Q4Y are maintained as they are.
Due to the switching, only the inductor LX connected to the second transformer 2X resonates with the panel capacitance Cp. Due to the resonance, the potential of the sustain electrode X rises from the negative peak value −Vt (see section C shown in FIG. 9). Thus, the polarity of the sustaining voltage pulse Vp changes from positive to negative.

When the potential of the sustain electrode X reaches the positive peak value Vt, the sustaining voltage pulse Vp reaches the negative peak value −2 Vt. At that time, the controller 31 turns on the first low-side main switch element Q2X and the second high-side main switch element Q3X for the second sustaining pulse generator 1X. Here, since the voltage across the switching elements Q2X and Q3X is substantially equal to zero, no switching loss occurs.
Due to the switching, the potential of the sustain electrode X is fixed to the positive peak value Vt, so that the discharge sustain pulse voltage Vp is fixed to the negative peak value −2 Vt (see section D shown in FIG. 9).

Similarly, when changing the polarity of the sustaining voltage pulse Vp from negative to positive, the controller 31 delays the switching operation of the second sustaining pulse generator 1X from the switching operation of the first sustaining pulse generator 1Y. .
In such switching control, the two inductors LY and LX alternately resonate with the panel capacitance Cp of the PDP 20 at every rising / falling of the sustaining voltage pulse Vp. Due to these resonances, power is efficiently exchanged between the panel capacitance Cp and the two inductors LY and LX. As a result, reactive power due to charging / discharging of the panel capacitance Cp is reduced.

  Further, at the end of the discharge sustain period, the control unit 31 may cause the PFC converter 40 to regenerate all the energy remaining in the two inductors LY and LX by switching control similar to that of the control unit 30 according to the first embodiment (see FIG. (Refer to section VI shown in 8 and 9). Thereby, the efficiency regarding the application of the sustaining voltage pulse is improved.

  As described above, the PDP driving apparatus according to the second embodiment of the present invention includes the two sustaining pulse generators 1Y and 1X. In the discharge sustain period, the power required for charging and discharging the panel capacitance Cp is supplied to the PDP 20 through both of the two discharge sustain pulse generators 1Y and 1X. In particular, for a certain sustaining voltage pulse Vp, the current flowing through each sustaining pulse generator 1Y, 1X may be half the current flowing through the sustaining pulse generator 1 according to the first embodiment. Therefore, the circuit elements included in the discharge sustain pulse generators 1Y and 1X may have a small current capacity. As a result, each of the sustaining pulse generators 1Y and 1X can be easily downsized.

  The PDP driving apparatus according to the second embodiment of the present invention further includes transformers 2Y and 2X on the output sides of the two sustaining pulse generators 1Y and 1X. In addition, the inductors LY and LX are connected to the secondary windings 2bY and 2bX of the transformers 2Y and 2X as in the first embodiment. The transformers 2Y and 2X and the inductors LY and LX have the same effects as the transformer 2 and the inductor L according to the first embodiment.

  Particularly in the PDP driving device according to the second embodiment of the present invention, the secondary windings 2bY and 2bX of the two transformers 2Y and 2X are connected in series with the panel capacitance Cp of the PDP 20 (see FIGS. 6 and 7). At that time, the secondary voltage of each of the transformers 2Y and 2X may be half the secondary voltage of the transformer 2 according to the first embodiment with respect to a constant discharge sustaining pulse voltage Vp. Accordingly, since the transformers 2Y and 2X may have low withstand voltages, the PDP driving device can be further reduced in size.

  In the PDP driving device according to the second embodiment of the present invention, as described above, the current / voltage of each discharge sustaining pulse generator 1Y, 1X may be half of the current / voltage in the sustaining pulse generator 1 according to the first embodiment. At that time, the power consumption of each discharge sustain pulse generator 1Y, 1X is substantially equal to 1/4 of the power consumption of the discharge sustain pulse generator 1 according to the first embodiment. That is, the power consumption of the two discharge sustain pulse generators 1Y and 1X is substantially equal to 1/2 of the power consumption of the discharge sustain pulse generator 1 according to the first embodiment. Thus, the PDP driving apparatus according to the second embodiment is superior to the PDP driving apparatus according to the first embodiment in terms of power saving.

<< Embodiment 3 >>
FIG. 10 is a block diagram showing a configuration of a plasma display according to Embodiment 3 of the present invention. In FIG. 10, the same reference numerals as those shown in FIG. 1 are given to the same constituent elements as those shown in FIG. Furthermore, the description about Embodiment 1 is used about the detail of those similar components.
The plasma display includes a PFC converter 40, a PDP driving device, a PDP 20, and a control unit 32. The PDP driving device includes a first driving unit 10A, a second driving unit 10B, and an initialization / scanning pulse generation unit 3.
The first driver 10A includes a first sustaining pulse generator 1A, a first transformer 2A, and a first inductor LA.
The second driver 10B includes a second sustaining pulse generator 1B, a second transformer 2B, and a second inductor LB.

In this plasma display, unlike the plasma display according to the second embodiment (see FIG. 6), the secondary windings 2bA and 2bB of the two transformers 2A and 2B are connected in parallel with the PDP 20 as follows.
The output terminals of the first sustaining pulse generator 1A are connected to both ends of the primary winding 2aA of the first transformer 2A.
The output terminals of the second sustaining pulse generator 1B are connected to both ends of the primary winding 2aB of the second transformer 2B.
One ends of the secondary windings 2bA and 2bB of the two transformers 2A and 2B are connected to the initialization / scanning pulse generator 3, and the other ends are grounded. On the other hand, the sustain electrodes X1, X2, X3,... Of the PDP 20 are grounded. As these ground conductors, a common ground conductor, for example, a frame (not shown) of the PDP 20 is used. In addition, the secondary windings 2bA and 2bB of the two transformers 2A and 2B may be directly connected to the sustain electrodes X1, X2, X3,.
The initialization / scanning pulse generator 3 separates the secondary windings 2bA, 2bB of the two transformers 2A, 2B from the scan electrodes Y1, Y2, Y3,... In the initialization / address period, and the scan electrodes in the discharge sustain period. Connect to Y1, Y2, Y3,.

  Unlike FIG. 10, one end of the secondary windings 2bA, 2bB of the two transformers 2A, 2B may be connected to the sustain electrodes X1, X2, X3,... Of the PDP 20 through a separation switch, and the other end may be grounded. In that case, the separation switch connects the sustain electrodes X1, X2, X3,... To the secondary windings 2bA and 2bB of the two transformers 2A and 2B in the discharge sustain period, and the secondary windings in the initialization / address period. Separate from lines 2bA and 2bB and ground. On the other hand, the initialization / scanning pulse generator 3 grounds the scan electrodes Y1, Y2, Y3,... During the discharge sustain period.

  The two inductors LA and LB are connected in parallel with the secondary windings 2bA and 2bB of the transformers 2A and 2B, respectively. Each of the inductors LA and LB is preferably an exciting inductance of the transformers 2A and 2B to be connected. In addition, the inductors LA and LB may be elements (auxiliary inductors) independent of the transformers 2A and 2B. In this case, preferably, the inductance of the auxiliary inductor is sufficiently smaller than the excitation inductance of the transformers 2A and 2B.

The control unit 32 controls switching of each of the two sustaining pulse generation units 1A and 1B, the initialization / scanning pulse generation unit 3, and the address electrode driving unit (not shown) according to the ADS method. In particular, the controller 32 synchronizes the primary pulse voltages VFA and VFB between the two discharge sustain pulse generators 1A and 1B.
The control unit 32 further determines an address electrode and a subfield to which the signal pulse voltage is applied based on the video signal. As a result, an image corresponding to the image signal is reproduced on the PDP 20.

  FIG. 11 is an equivalent circuit diagram of the first drive unit 10A, the second drive unit 10B, and the PDP 20. Here, the equivalent circuit of the PDP 20 is represented only by the sustain electrode X, the scan electrode Y, and the capacitance between these electrodes X and Y, that is, the panel capacitance Cp, as in FIG. The path of current flowing through the PDP 20 during discharge in the discharge cell is omitted.

The two sustaining pulse generators 1A and 1B both have the same circuit configuration as the sustaining pulse generator 1 according to the first embodiment, and particularly include a full bridge inverter (see FIG. 2). In particular, the characteristics of the common circuit elements are substantially equal between the two discharge sustaining pulse generators 1A and 1B. Similarly, the two transformers 2A and 2B and the two inductors LA and LB have substantially the same characteristics.
In addition, each discharge sustaining pulse generation unit may include a half-bridge type inverter similarly to the discharge sustaining pulse generation unit according to the first embodiment.
In FIG. 11, the same reference numerals as those shown in FIG. 2 are given to circuit elements similar to the circuit elements shown in FIG. Further, the description of the first embodiment is used for details of the similar circuit elements.

The secondary windings 2bA and 2bB of the two transformers 2A and 2B are connected with the same polarity as shown in FIG. 11, for example. At that time, the controller 32 maintains the switching operations of the two sustaining pulse generators 1A and 1B in substantially the same phase. That is, the corresponding main switch elements are turned on / off between the two sustaining pulse generating sections 1A, 1B.
The secondary windings 2bA and 2bB of the two transformers 2A and 2B may be connected with opposite polarities, apart from the example shown in FIG. At that time, the control unit 32 maintains the switching operations of the two sustaining pulse generating units 1A and 1B in substantially opposite phases.

The switching operation of the two sustaining pulse generators 1A and 1B is common to the switching operation of the sustaining pulse generator 1 according to the first embodiment. Therefore, in the discharge sustain period, the potential change of the scan electrode Y of the PDP 20 is the same as the potential change according to the first embodiment (see FIG. 5). That is, the sustaining voltage pulse Vp is the same as that according to the first embodiment.
In particular, at the rise / fall of the sustaining voltage pulse Vp, the two inductors LA and LB simultaneously resonate with the panel capacitance Cp of the PDP 20. Due to these resonances, power is efficiently exchanged between the panel capacitance Cp and the two inductors LA and LB. As a result, reactive power due to charging / discharging of the panel capacitance Cp is reduced.

  The control unit 32 may further regenerate all the energy remaining in the two inductors LA and LB in the PFC converter 40 by switching control similar to that of the control unit 30 according to the first embodiment at the end of the discharge sustain period. Thereby, the efficiency regarding the application of the sustaining voltage pulse is improved.

  As described above, the PDP driving device according to the third embodiment of the present invention includes the two sustaining pulse generators 1A and 1B. In the discharge sustain period, the power required for charging and discharging the panel capacitance Cp is supplied to the PDP 20 through both of the two discharge sustain pulse generators 1A and 1B. In particular, for a certain sustaining voltage pulse Vp, the current flowing through each sustaining pulse generator 1A, 1B may be half the current flowing through the sustaining pulse generator 1 according to the first embodiment. Therefore, the circuit elements included in the discharge sustain pulse generators 1A and 1B may have a small current capacity. As a result, each of the sustaining pulse generators 1A and 1B can be easily downsized.

  The PDP driving apparatus according to the third embodiment of the present invention further includes transformers 2A and 2B on the output sides of the two sustaining pulse generation units 1A and 1B. In addition, the inductors LA and LB are connected to the secondary windings 2bA and 2bB of the transformers 2A and 2B as in the first embodiment. The transformers 2A and 2B and the inductors LA and LB provide the same effects as the transformer 2 and the inductor L according to the first embodiment.

  Unlike the apparatus according to the second embodiment, the PDP driving apparatus according to the third embodiment of the present invention has two driving units 10A and 10B integrated on the same side with respect to the PDP 20 (see FIG. 10). In this case, for example, since the heat / noise sources included in the two drive units 10A and 10B are contained in a relatively narrow range, it is relatively easy to take effective heat / noise countermeasures.

<< Embodiment 4 >>
In the plasma display according to the fourth embodiment of the present invention, unlike the plasma display according to the first embodiment, the PDP driving apparatus 10 includes the power recovery unit 4 on the primary side of the transformer 2 instead of the inductor L (see FIG. 12). Other than that, the configuration of both plasma displays is the same (see Figure 1).
In FIG. 12, the same components as those shown in FIG. 1 are denoted by the same reference numerals as those shown in FIG. Furthermore, the description about Embodiment 1 is used about the detail of those similar components.

  The power recovery unit 4 is connected to the primary winding 2a of the transformer 2 and includes an inverter and a switch unit. For example, the switch unit is turned on each time the primary pulse voltage VF sent from the sustaining pulse generating unit 1 rises / falls, and connects the inverter to the primary winding 2a of the transformer 2. The inverter then resonates with the panel capacitance of PDP 20 through transformer 2.

  Similar to the control unit 30 according to the first embodiment, the control unit 33 controls switching of each of the sustaining pulse generating unit 1, the initialization / scanning pulse generating unit 3, and the address electrode driving unit (not shown) according to the ADS method. The control unit 33 further controls the switching operation of the power recovery unit 4 during the discharge sustaining period, and synchronizes with the switching operation of the discharge sustaining pulse generating unit 1.

FIG. 13 is an equivalent circuit diagram of the sustaining pulse generating unit 1, the power recovery unit 4, the transformer 2, and the PDP 20. In FIG. 13, the same components as those shown in FIG. 2 are denoted by the same reference numerals as those shown in FIG. Furthermore, the description about Embodiment 1 is used about the detail of those similar components.
The initialization / scanning pulse generator 3 is connected to the position shown in FIG. 2 and simply short-circuits between the secondary winding 2b of the transformer 2 and the scan electrode Y in the discharge sustain period. In FIG. 13, the initialization / scanning pulse generator 3 is omitted.

The power recovery unit 4 includes two recovery switch elements Q5 and Q6, two diodes D1 and D2, and an inductor L.
The two recovery switch elements Q5 and Q6 are preferably MOSFETs. In addition, an IGBT or a bipolar transistor may be used.
The two diodes D1 and D2 are connected in parallel with the recovery switch elements Q5 and Q6, respectively. Thereby, the parallel connection of the recovery switch element and the diode has polarity. When the recovery switch elements Q5 and Q6 are MOSFETs, the diodes D1 and D2 may be body diodes of the recovery switch elements Q5 and Q6.
The inductor L is preferably an element independent of the transformer 2. In addition, the leakage inductance of the transformer 2 may be used.

The two recovery switch elements Q5 and Q6 and the inductor L are connected in series. The series connection is connected in parallel with the primary winding 2a of the transformer 2.
The terminals of the same polarity of the parallel connection (Q5 and D1, Q6 and D2) of the recovery switch element and the diode are connected to each other through the inductor L (or directly). For example, in FIG. 13, the anodes of two diodes D1 and D2 are connected through an inductor L.
Thus, the two recovery switch elements Q5 and Q6 and the two diodes D1 and D2 constitute a bidirectional switch.

The configuration of the bidirectional switch is not limited to the example shown in FIG. 13, and any configuration that can invert the current IL flowing through the inductor L may be used. For example, the two diodes D1 and D2 may be replaced with switch elements, respectively. At that time, the control unit 33 controls the on / off timings of these switch elements to coincide with the on / off timings of the original diodes D1 and D2.
In addition, the bidirectional switch may be a series connection of two sets of switch elements and diodes connected in parallel with opposite polarities.

The control unit 33 (see FIG. 12) controls the voltage across the panel capacitance Cp, that is, the polarity of the sustaining voltage pulse Vp from the positive as follows by ON / OFF control for the main switch elements Q1 to Q4 and the recovery switch elements Q5 and Q6. Change to negative.
The first high-side main switch element Q1 and the second low-side main switch element Q4 are kept on, and the other switch elements Q2, Q3, Q5, Q6 are kept off. At that time, the potential of the scan electrode Y, that is, the sustaining voltage pulse Vp is maintained at a positive peak value. Here, the peak value is determined by the potential Vs of the input terminal 1T of the sustaining pulse generator 1 and the winding ratio of the transformer 2.
When the discharge is maintained in the PDP 20, power for maintaining the discharge current is supplied from the PFC converter 40 to the PDP 20 through the input terminal 1T and the transformer 2.

When the state is maintained for a predetermined time corresponding to the pulse width of the sustaining voltage pulse, the control unit 33 turns off the first high-side main switch element Q1 and the second low-side main switch element Q4, One recovery switch element Q5 is turned on. Since the current is substantially equal to zero in the two main switch elements Q1 and Q4, no switching loss occurs.
As a result of the switching, the loop of the primary winding 2a of the transformer 2 → the first recovery switch element Q5 → the inductor L → the second diode D2 → the primary winding 2a of the transformer 2 becomes conductive (the arrow indicates the direction of current). (See Figure 13). At that time, the inductor L and the panel capacitance Cp resonate through the transformer 2. The resonance current IL flows through the loop in the direction of the arrow. Further, the potential of the scan electrode Y drops from the positive peak value. Since sustain electrode X is maintained at the ground voltage, discharge sustain pulse voltage Vp drops.

The potential of the scan electrode Y, that is, the sustaining voltage pulse Vp reaches a negative peak value. At the same time, the resonance current IL is attenuated to substantially zero, so that the second diode D2 is turned off.
At that time, the controller 33 turns off the first recovery switch element Q5 and turns on the first low-side main switch element Q2 and the second high-side main switch element Q3. Since the current is substantially equal to zero in the first recovery switch element Q5, no switching loss occurs. In the two main switch elements Q2 and Q3, since the voltage between both ends is equal to zero, no switching loss occurs.
Thus, the sustaining voltage pulse Vp is clamped to a negative peak value.
When the discharge is maintained in the PDP 20, power for maintaining the discharge current is supplied from the PFC converter 40 to the PDP 20 through the input terminal 1T and the transformer 2.

Similarly, the control unit 33 changes the polarity of the sustaining voltage pulse Vp from negative to positive by on / off control for the main switch elements Q1 to Q4 and the recovery switch elements Q5 and Q6.
When the polarity of the sustaining voltage pulse Vp is reversed, the panel capacitance Cp of the PDP 20 and the inductor L of the power recovery unit 4 resonate as described above. Due to the resonance, the polarity of the sustaining voltage pulse Vp is reversed with little power consumption. As a result, reactive power resulting from charging / discharging of the panel capacitance Cp of the PDP 20 is reduced.

  The PDP driving apparatus according to Embodiment 4 of the present invention has a transformer 2 on the output side of the sustaining pulse generator 1 as in the apparatus according to Embodiment 1. The transformer 2 gives the same effect as the transformer 2 according to the first embodiment.

In the PDP driving device according to the fourth embodiment of the present invention, the power recovery unit 4 further reduces the reactive power due to the charging / discharging of the panel capacity.
In the power recovery unit 4, in particular, the ON periods of the recovery switch elements Q5 and Q6 coincide with the rising period and the falling period of the discharge sustaining pulse voltage Vp with high accuracy as described above. That is, current does not flow through the inductor L except during those periods.
Thus, the resonance period of the inductor L and the panel capacitance Cp is surely limited to the rising period and the falling period of the sustaining voltage pulse Vp.

<< Embodiment 5 >>
In the plasma display according to the fifth embodiment of the present invention, unlike the plasma display according to the second embodiment, the two drive units 10Y and 10X are replaced with the inductors LY and LX, respectively, and the power recovery units 4Y and 4X are the primary transformers 2Y and 2X. Included on the side (see Figure 14). Other than that, the configuration of both plasma displays is the same (see FIG. 6).
In FIG. 14, the same components as those shown in FIG. 6 are denoted by the same reference numerals as those shown in FIG. Furthermore, the description about Embodiment 2 is used about the detail of those similar components.

In each of the drive units 10Y and 10X, the configuration of the discharge sustain pulse generators 1Y and 1X, the power recovery units 4Y and 4X, and the transformers 2Y and 2X are the same as those in the discharge sustain pulse generator 1, the power recovery unit 4 and the fourth embodiment. The configuration of the transformer 2 is the same. In particular, the characteristics of the circuit elements corresponding to each other are substantially equal.
Similarly to the control unit 31 according to the second embodiment, the control unit 34 includes two sustaining pulse generation units 1Y and 1X, an initialization / scanning pulse generation unit 3Y, an initialization pulse generation unit 3X, and an address electrode drive unit (not shown). ) Control each switching according to the ADS system.
Further, the control unit 34 controls the switching operation of the power recovery units 4Y and 4X during the discharge sustain period, and synchronizes with the switching operation of the discharge sustain pulse generating units 1Y and 1X. In addition, the two primary pulse voltages VFY and VFX sent from the two sustaining pulse generators 1Y and 1X are synchronized.

FIG. 15 is an equivalent circuit diagram of the two sustaining pulse generation units 1Y and 1X, the two power recovery units 4Y and 4X, the two transformers 2Y and 2X, and the PDP 20. In FIG. 15, the same components as those shown in FIG. 7 are denoted by the same reference symbols as those shown in FIG. Furthermore, the description about Embodiment 2 is used about the detail of those similar components.
The initialization / scanning pulse generating unit 3Y is connected to the position shown in FIG. 7, and simply shorts between the secondary winding 2bY of the first transformer 2Y and the scanning electrode Y in the discharge sustain period.
The initialization pulse generator 3X is connected to the position shown in FIG. 7, and simply shorts between the secondary winding 2bX of the second transformer 2X and the sustain electrode X in the discharge sustain period.
In FIG. 15, the initialization / scanning pulse generator 3Y and the initialization pulse generator 3X are omitted.

The secondary windings 2bY and 2bX of the two transformers 2Y and 2X are connected with their polarities reversed, for example, as shown in FIG. At that time, the control unit 34 maintains the switching operation of the two sustaining pulse generation units 1Y and 1X and the switching operation of the two power recovery units 4Y and 4X in substantially the same phase.
Apart from the example shown in FIG. 15, the secondary windings 2bY and 2bX of the two transformers 2Y and 2X may be connected with the same polarity. At that time, the controller 34 maintains the switching operations of the two sustaining pulse generators 1Y and 1X and the switching operations of the two power recovery units 4Y and 4X in substantially opposite phases.

The switching operations of the two sustaining pulse generating units 1Y and 1X and the two power recovery units 4Y and 4X are the same as the switching operations of the sustaining pulse generating unit 1 and the power recovery unit 4 according to the fourth embodiment, respectively. Therefore, the potential change of the scan electrode Y of the PDP 20 is maintained in the opposite phase to the potential change of the sustain electrode X. Therefore, the sustaining pulse voltage Vp applied between the scan electrode Y and the sustain electrode X is the same as that according to the fourth embodiment.
In particular, the inductor L of the power recovery units 4Y and 4X simultaneously resonates with the panel capacitance Cp of the PDP 20 at every rise / fall of the sustaining voltage pulse Vp. Due to these resonances, power is efficiently exchanged between the inductor L and the panel capacitance Cp. As a result, reactive power due to charging / discharging of the panel capacitance Cp is reduced.

In addition to the above switching control, the control unit 34 may set the following phase difference (greater than 0 ° and smaller than 180 °) between the switching operations of the two sustaining pulse generation units 1Y and 1X ( (See Figure 16).
For example, it is assumed that the secondary windings 2bY and 2bX of the two transformers 2Y and 2X are connected with opposite polarities (see FIG. 15).

  The first high-side main switch element Q1 and the second low-side main switch element Q4 remain on in both of the two sustaining pulse generators 1Y and 1X, and the other switch elements Q2, Q3, Q5, and Q6 Remains off. At that time, the potential of the scan electrode Y is maintained at the positive peak value Vt, and the potential of the sustain electrode X is maintained at the negative peak value −Vt (see section A shown in FIG. 16). Accordingly, the sustaining voltage pulse Vp is maintained at the positive peak value 2Vt. Here, the peak value Vt is determined by the potential Vs of the input terminal 1T of the sustaining pulse generators 1Y and 1X and the winding ratio of the transformers 2Y and 2X.

When the state is maintained for a predetermined time corresponding to the pulse width of the discharge sustaining pulse voltage, the control unit 34, for the first discharge sustaining pulse generating unit 1Y, the first high-side main switch element Q1 and the second The low side main switch element Q4 is turned off. At that time, since the current is substantially equal to zero in the first sustaining pulse generator 1A, no switching loss occurs.
On the other hand, for the second sustaining pulse generator 1X, the on / off states of the four main switch elements Q1 to Q4 are maintained as they are.
Furthermore, the control unit 34 turns on the first recovery switch element Q5 for the first power recovery unit 4Y.
Due to the switching, only the inductor L of the first power recovery unit 4Y resonates with the panel capacitance Cp of the PDP 20. The resonance current IL flows through the inductor L of the first power recovery unit 4Y, and the potential of the scan electrode Y drops from the positive peak value Vt (see section B shown in FIG. 16). Therefore, the sustaining voltage pulse Vp drops from the positive peak value 2Vt.

When the potential of the scan electrode Y reaches the negative peak value −Vt, the sustaining pulse voltage Vp reaches zero. At the same time, since the resonance current IL is attenuated to substantially zero, the second diode D2 is turned off in the first power recovery unit 4Y.
At that time, the controller 34 turns off the first high-side main switch element Q1 and the second low-side main switch element Q4 for the second sustaining pulse generator 1X. In the second sustaining pulse generator 1X, since the current is substantially equal to zero, no switching loss occurs.
The control unit 34 further turns off the first recovery switch element Q5 for the first power recovery unit 4Y. At that time, since the resonance current IL is substantially equal to zero, no switching loss occurs.
Subsequently, the control unit 34 turns on the first low-side main switch element Q2 and the second high-side main switch element Q3 for the first sustaining pulse generation unit 1Y. On the other hand, for the second sustaining pulse generator 1X, the on / off states of the four main switch elements Q1 to Q4 are maintained as they are.
Furthermore, the control unit 34 turns on the first recovery switch element Q5 for the second power recovery unit 4X.
Due to the switching, only the inductor L of the second power recovery unit 4X resonates with the panel capacitance Cp. The resonance current IL flows through the inductor L of the second power recovery unit 4X, and the potential of the sustain electrode X rises from the negative peak value −Vt (see section C shown in FIG. 16). Thus, the polarity of the sustaining voltage pulse Vp changes from positive to negative.

When the potential of the sustain electrode X reaches the positive peak value Vt, the sustaining voltage pulse Vp reaches the negative peak value −2 Vt. At the same time, since the resonance current IL is attenuated to substantially zero, the second diode D2 is turned off in the second power recovery unit 4X.
At that time, the control unit 34 turns off the first recovery switch element Q5 for the second power recovery unit 4X. Here, since the resonance current IL is substantially equal to zero, no switching loss occurs.
Further, the controller 34 turns on the first low-side main switch element Q2 and the second high-side main switch element Q3 for the second sustaining pulse generator 1X. In these main switch elements Q2 and Q3, the voltage across the terminals is substantially equal to zero, so that no switching loss occurs.
Due to the switching, the potential of the sustain electrode X is fixed at the positive peak value Vt, so that the discharge sustain pulse voltage Vp is fixed at the negative peak value −2 Vt (see section D shown in FIG. 16).

Similarly, when the polarity of the sustaining voltage pulse Vp is changed from negative to positive, the control unit 34 performs the switching operation of the second sustaining pulse generator 1X and the second power recovery unit 4X with the first discharge. Delayed from the switching operation of sustain pulse generator 1Y and first power recovery unit 4Y.
In such switching control, every time the discharge sustaining pulse voltage Vp rises / falls, the inductors L of the two power recovery units 4Y and 4X resonate with the panel capacitance Cp of the PDP 20 alternately. Due to these resonances, power is efficiently exchanged between the panel capacitance Cp and the two inductors L. As a result, reactive power due to charging / discharging of the panel capacitance Cp is reduced.

Similar to the apparatus according to the second embodiment, the PDP driving apparatus according to the fifth embodiment of the present invention includes two discharge sustaining pulse generators 1Y and 1X and transformers 2Y and 2X on the output side thereof. They give the same effects as those according to the second embodiment.
In particular, the secondary windings 2bY and 2bX of the two transformers 2Y and 2X are connected in series with the panel capacitance Cp of the PDP 20 as in the second embodiment (see FIG. 15). Therefore, the PDP driving apparatus according to the fifth embodiment can be further reduced in size as in the second embodiment, and is superior in terms of power saving than the PDP driving apparatus according to the fourth embodiment.

  Further, in the PDP driving device according to the fifth embodiment of the present invention, as in the device according to the fourth embodiment, the power recovery units 4Y and 4X reduce the reactive power caused by the charging / discharging of the panel capacity. Therefore, the resonance period between the inductor L and the panel capacitance Cp is reliably limited to the rising period and the falling period of the sustaining voltage pulse Vp.

Embodiment 6
In the plasma display according to the sixth embodiment of the present invention, unlike the plasma display according to the third embodiment, the two driving units 10A and 10B are replaced with the inductors LA and LB, respectively, and the power recovery units 4A and 4B are the primary transformers 2A and 2B. Included on the side (see Figure 17). Other than that, the configuration of both plasma displays is the same (see FIG. 10).
In FIG. 17, the same components as those shown in FIG. 10 are denoted by the same reference numerals as those shown in FIG. Furthermore, the description about Embodiment 3 is used about the detail of those similar components.

In each drive unit 10A, 10B, the configuration of the discharge sustain pulse generators 1A, 1B, the power recovery units 4A, 4B, and the transformers 2A, 2B are the same as those of the discharge sustain pulse generator 1, the power recovery unit 4, and The configuration of the transformer 2 is the same. In particular, the characteristics of the circuit elements corresponding to each other are substantially equal.
Similarly to the control unit 32 according to the third embodiment, the control unit 35 switches the two sustaining pulse generation units 1A and 1B, the initialization / scanning pulse generation unit 3, and the address electrode driving unit (not shown) to the ADS system. Control according to.
The control unit 35 further controls the switching operation of the power recovery units 4A and 4B during the discharge sustain period, and synchronizes with the switching operation of the discharge sustain pulse generation units 1A and 1B. In addition, the two primary pulse voltages VFA and VFB sent from the two sustaining pulse generators 1A and 1B are synchronized.

FIG. 18 is an equivalent circuit diagram of the two sustaining pulse generation units 1A and 1B, the two power recovery units 4A and 4B, the two transformers 2A and 2B, and the PDP 20. In FIG. 18, the same reference numerals as those shown in FIG. 11 are given to the same constituent elements as those shown in FIG. Furthermore, the description about Embodiment 3 is used about the detail of those similar components.
The initialization / scanning pulse generator 3 is connected to the position shown in FIG. 11, and simply shorts between the secondary windings 2bA and 2bB of the two transformers 2A and 2B and the scanning electrode Y in the discharge sustain period. In FIG. 18, the initialization / scanning pulse generator 3 is omitted.

The secondary windings 2bA and 2bB of the two transformers 2A and 2B are connected with the same polarity as shown in FIG. 18, for example. At that time, the control unit 35 maintains the switching operations of the two discharge sustaining pulse generating units 1A and 1B and the two power recovery units 4A and 4B in substantially the same phase.
The secondary windings 2bA and 2bB of the two transformers 2A and 2B may be connected with their polarities reversed, apart from the example shown in FIG. At that time, the control unit 35 maintains the switching operations of the two sustaining pulse generating units 1A and 1B and the two power recovery units 4A and 4B in substantially opposite phases.

The switching operation of the two sustaining pulse generation units 1A and 1B and the two power recovery units 4Y and 4X is the same as the switching operation of the sustaining pulse generation unit 1 and the power recovery unit 4 according to the fourth embodiment. Therefore, the potential change of the scan electrode Y of the PDP 20 is maintained in the opposite phase to the potential change of the sustain electrode X. Therefore, the sustaining pulse voltage Vp applied between the scan electrode Y and the sustain electrode X is the same as that according to the fourth embodiment.
In particular, at each rise / fall of the sustaining voltage pulse Vp, the inductors L of the power recovery units 4A and 4B simultaneously resonate with the panel capacitance Cp of the PDP 20. Due to these resonances, power is efficiently exchanged between the inductor L and the panel capacitance Cp. As a result, reactive power due to charging / discharging of the panel capacitance Cp is reduced.

  Similar to the apparatus according to the third embodiment, the PDP driving apparatus according to the sixth embodiment of the present invention includes two discharge sustaining pulse generators 1A and 1B and transformers 2A and 2B on the output side thereof. They give the same effect as that according to the third embodiment.

  Further, in the PDP driving apparatus according to the sixth embodiment of the present invention, as in the apparatus according to the fourth embodiment, the power recovery units 4A and 4B reduce the reactive power due to the charging / discharging of the panel capacity. Therefore, the resonance period between the inductor L and the panel capacitance Cp is reliably limited to the rising period and the falling period of the sustaining voltage pulse Vp.

<< Embodiment 7 >>
In the PDP driving device according to the fourth embodiment of the present invention, the specific circuit configuration of the power recovery unit 4 is not limited to that shown in FIG. 13 and may be various.
In the PDP driving device according to Embodiment 7 of the present invention, the power recovery unit 4 has the following configuration (see FIG. 19). Here, the components other than the power recovery unit 4 are the same as those according to the fourth embodiment (see FIG. 13).
In FIG. 19, the same components as those shown in FIG. 13 are denoted by the same reference numerals as those shown in FIG. Furthermore, the description about Embodiment 4 is used about the detail of those similar components.

The power recovery unit 4 includes two similar circuit portions 4a and 4b. Each portion 4a, 4b includes a capacitor C, a high side recovery switch element Q5, a low side recovery switch element Q6, a high side diode D1, a low side diode D2, and an inductor L.
The capacity of the capacitor C is sufficiently larger than the panel capacity Cp of the PDP 20. The voltage across the capacitor C is maintained substantially equal to the half value Vs / 2 of the DC voltage Vs applied to the input terminal 1T of the sustaining pulse generator 1.
The two recovery switch elements Q5 and Q6 are preferably MOSFETs. In addition, an IGBT or a bipolar transistor may be used.
The inductor L is preferably an element independent of the transformer 2. In addition, the leakage inductance of the transformer 2 may be used.

One end of the capacitor C is grounded, and the other end is connected to one end of each recovery switch element Q5, Q6. The other end of the high side recovery switch element Q5 is connected to the anode of the high side diode D1. The cathode of the high side diode D1 is connected to the anode of the low side diode D2. The cathode of the low side diode D2 is connected to the other end of the low side recovery switch element Q6.
The inductor L is connected between the connection point J1 (or J2) of the series connection Q1, Q2 (or Q3, Q4) of the two main switch elements and the connection point J3 of the high side diode D1 and the low side diode D2. The

The controller 33 (see FIG. 12) changes the polarity of the sustaining voltage pulse Vp from positive to negative by the on / off control for the main switch elements Q1 to Q4 and the recovery switch elements Q5 and Q6 as follows.
When the first high-side main switch element Q1 and the second low-side main switch element Q4 are kept on, the potential of the scan electrode Y, that is, the sustaining voltage pulse Vp is maintained at a positive peak value (maintain Electrode X is maintained at ground voltage). Here, the peak value is determined by the potential Vs of the input terminal 1T of the sustaining pulse generator 1 and the winding ratio of the transformer 2.
When the discharge is maintained in the PDP 20, power for maintaining the discharge current is supplied from the PFC converter 40 to the PDP 20 through the input terminal 1T and the transformer 2.

When the state is maintained for a predetermined time corresponding to the pulse width of the sustaining voltage pulse, the control unit 33 turns off the first high-side main switch element Q1, and the first portion 4a of the power recovery unit 4 The recovery switch element Q6 is turned on. Since the current is substantially equal to zero in the first high-side main switching device Q1, no switching loss occurs.
In the sustaining pulse generator 1 and the first part 4a of the power recovery unit 4, the ground terminal ← capacitor C ← low side recovery switch element Q6 ← low side diode D2 ← inductor L ← primary winding 2a of transformer 2 ← second The low-side main switch element Q4 ← the loop of the ground terminal becomes conductive (the arrow indicates the direction of current, see FIG. 19). At that time, the inductor L and the panel capacitance Cp resonate through the transformer 2. The resonance current IL flows through the loop in the direction of the arrow. Furthermore, the potential of the scan electrode Y, that is, the sustaining voltage pulse Vp drops.

When the resonance current IL is attenuated to substantially zero, the low-side diode D2 is turned off. At the same time, the sustaining voltage pulse Vp reaches zero. At that time, the controller 33 turns off the low-side recovery switch element Q6 and turns on the first low-side main switch element Q2. In the first low-side main switch element Q2, the voltage across the terminals is equal to zero, so that no switching loss occurs.
Thus, the sustaining voltage pulse Vp is clamped to zero.

Subsequently, the control unit 33 turns off the second low-side main switch element Q4, and turns on the high-side recovery switch element Q5 in the second portion 4b of the power recovery unit 4. In the second low-side main switch element Q4, the voltage across the terminal is equal to zero, so that no switching loss occurs.
In the sustaining pulse generator 1 and the second part 4b of the power recovery unit 4, the ground terminal ← the first low-side main switch element Q2 ← the primary winding 2a of the transformer 2 ← the inductor L ← the high-side diode D1 ← the high-side Recovery switch element Q5 ← capacitor C ← ground terminal loop conducts (the arrow indicates the direction of current, see FIG. 19). At that time, the inductor L and the panel capacitance Cp resonate through the transformer 2. The resonance current IL flows through the loop in the direction of the arrow. Furthermore, the sustaining voltage pulse Vp drops.

When the resonance current IL is attenuated to substantially zero, the high-side diode D1 is turned off. At the same time, the sustaining voltage pulse Vp reaches a negative peak value. At that time, the controller 33 turns off the high-side recovery switch element Q5 and turns on the second high-side main switch element Q3. Here, since the voltage across the second high-side main switching device Q3 is equal to zero, no switching loss occurs.
Thus, the sustaining voltage pulse Vp is clamped to a negative peak value.
When the discharge is maintained in the PDP 20, power for maintaining the discharge current is supplied from the PFC converter 40 to the PDP 20 through the input terminal 1T and the transformer 2.

Similarly, the control unit 33 changes the polarity of the sustaining voltage pulse Vp from negative to positive by on / off control for the main switch elements Q1 to Q4 and the recovery switch elements Q5 and Q6.
When the polarity of the sustaining voltage pulse Vp changes from positive to negative, in the power recovery unit 4, the capacitor C in the first portion 4a recovers power from the panel capacitance Cp, while the capacitor C in the second portion 4b Power is supplied to the panel capacitance Cp. The opposite is true when the polarity of the sustaining voltage pulse Vp changes from negative to positive.
Thus, at the rise / fall of the sustaining voltage pulse Vp, the panel capacitance Cp of the PDP 20 and the inductor L of the power recovery unit 4 resonate, and power is efficiently transmitted between the panel capacitance Cp and the capacitor C of the power recovery unit 4. Exchanged. As a result, reactive power due to charging / discharging of the panel capacity is reduced.
That is, in the PDP driving device according to the seventh embodiment of the present invention, the power recovery unit 4 functions in the same manner as that according to the fourth embodiment and provides the same effect.

Embodiment 8
In the PDP driving device according to the fifth embodiment of the present invention (see FIG. 14), the specific circuit configuration of the two power recovery units 4Y and 4X is not limited to that shown in FIG. 15, but may be various.
In the PDP driving device according to the eighth embodiment of the present invention, the two power recovery units 4Y and 4X each have the same configuration as that according to the seventh embodiment (see FIGS. 19 and 20). Here, the components other than the power recovery units 4Y and 4X are the same as those according to the fifth embodiment (see FIGS. 14 and 15).
In FIG. 20, the same components as those shown in FIGS. 15 and 19 are denoted by the same reference numerals as those shown in FIGS. Furthermore, the description about Embodiment 5 and 7 is used about the detail of those similar components.

The secondary windings 2bY and 2bX of the two transformers 2Y and 2X are connected with their polarities reversed as shown in FIG. 20, for example. At that time, the control unit 34 (see FIG. 14) maintains the switching operation of the two sustaining pulse generation units 1Y and 1X and the switching operation of the two power recovery units 4Y and 4X in substantially the same phase.
Apart from the example shown in FIG. 20, the secondary windings 2bY and 2bX of the two transformers 2Y and 2X may be connected with the same polarity. At that time, the controller 34 maintains the switching operations of the two sustaining pulse generators 1Y and 1X and the switching operations of the two power recovery units 4Y and 4X in substantially opposite phases.

The switching operation between the two sustaining pulse generating units 1Y and 1X and the two power recovery units 4Y and 4X is the same as the switching operation between the sustaining pulse generating unit 1 and the power recovery unit 4 according to the seventh embodiment. Therefore, the potential change of the scan electrode Y of the PDP 20 is maintained in the opposite phase to the potential change of the sustain electrode X. Therefore, the sustaining pulse voltage Vp applied between the scan electrode Y and the sustain electrode X is the same as that according to the seventh embodiment.
In particular, the inductor L of the power recovery units 4Y and 4X simultaneously resonates with the panel capacitance Cp of the PDP 20 at every rise / fall of the sustaining voltage pulse Vp. Due to these resonances, power is efficiently exchanged between the capacitors C of the power recovery units 4Y and 4X and the panel capacitance Cp. As a result, reactive power due to charging / discharging of the panel capacitance Cp is reduced.

  Separately from the above, the control unit 34 determines the phase of the switching operation between the second discharge sustaining pulse generation unit 1X and the second power recovery unit 4X, the first discharge sustaining pulse generation unit 1Y and the first power recovery unit It may be delayed from the phase of the switching operation with 4Y (see FIG. 16). As a result, the inductor L of the two power recovery units 4Y and 4X alternately resonates with the panel capacitance Cp of the PDP 20 at every rising / falling of the sustaining voltage pulse Vp. Due to these resonances, power is efficiently exchanged between the two capacitors C and the panel capacitance Cp. As a result, reactive power resulting from charging / discharging of the panel capacitance Cp is reduced.

  In the PDP driving device according to the eighth embodiment of the present invention, the power recovery units 4Y and 4X function in the same manner as those according to the fifth embodiment as described above, and provide the same effects.

In the PDP drive device according to Embodiment 6 of the present invention (see FIG. 17), the specific circuit configuration of the two power recovery units 4A and 4B is not limited to that shown in FIG. It can be something. For example, the two power recovery units 4A and 4B may each have the same configuration as that according to the seventh embodiment (see FIG. 19). Here, the components other than the power recovery units 4A and 4B are the same as those according to the sixth embodiment (see FIGS. 17 and 18).
In particular, the control unit 35 (see FIG. 17) maintains the switching operations of the two discharge sustaining pulse generating units 1A and 1B and the two power recovery units 4A and 4B in the same phase (or opposite phase), respectively. As a result, the two power recovery units 4A and 4B function in the same manner as in the sixth embodiment and provide the same effects.

Embodiment 9
In the PDP driving device according to Embodiment 4 of the present invention (see FIG. 12), the power recovery unit 4 may have the following circuit configuration instead of the one shown in FIG. 13 (see FIG. 21). . Here, the components other than the power recovery unit 4 are the same as those according to the fourth embodiment (see FIGS. 12 and 13).
In FIG. 21, the same components as those shown in FIG. 13 are denoted by the same reference numerals as those shown in FIG. Furthermore, the description about Embodiment 4 is used about the detail of those similar components.

The sustaining pulse generator 1 further includes two diodes D1 and D2.
The anode of the high side diode D1 is connected to the first high side main switch element Q1, and the cathode is connected to the anode of the low side diode D2. The cathode of the low side diode D2 is connected to the first low side main switch element Q2. A connection point J1 between the two diodes D1 and D2 is connected to the primary winding 2a of the transformer 2.

The power recovery unit 4 includes two recovery switch elements Q5 and Q6 and an inductor L.
The two recovery switch elements Q5 and Q6 are preferably MOSFETs. In addition, an IGBT or a bipolar transistor may be used.
The inductor L is preferably an element independent of the transformer 2. In addition, the leakage inductance of the transformer 2 may be used.
The two recovery switch elements Q5 and Q6 are connected in series between the input terminal 1T and the ground terminal. An inductor L is connected between a connection point J1 of the two diodes D1 and D2 and a connection point J3 of the two recovery switch elements Q5 and Q6.

The control unit 33 (see FIG. 12) controls the voltage across the panel capacitance Cp, that is, the polarity of the sustaining voltage pulse Vp from the positive as follows by ON / OFF control for the main switch elements Q1 to Q4 and the recovery switch elements Q5 and Q6. Change to negative.
The first high-side main switch element Q1 and the second low-side main switch element Q4 are kept on, and the other switch elements Q2, Q3, Q5, Q6 are kept off. At that time, the potential of the scan electrode Y, that is, the sustaining voltage pulse Vp is maintained at a positive peak value. Here, the peak value is determined by the potential Vs of the input terminal 1T of the sustaining pulse generator 1 and the winding ratio of the transformer 2.
When the discharge is maintained in the PDP 20, power for maintaining the discharge current is supplied from the PFC converter 40 to the PDP 20 through the input terminal 1T and the transformer 2.

When the state is maintained for a predetermined time corresponding to the pulse width of the sustaining voltage pulse, the control unit 33 turns off the first high-side main switch element Q1 and turns on the low-side recovery switch element Q6. Since the current is substantially equal to zero in the first high-side main switching device Q1, no switching loss occurs.
By the switching, the loop of the ground terminal ← low side recovery switch element Q6 ← inductor L ← primary winding 2a of the transformer 2 ← second low side main switch element Q4 ← ground terminal is conducted (the arrow indicates the direction of current). 21). At that time, the inductor L and the panel capacitance Cp resonate through the transformer 2. The resonance current IL flows through the loop in the direction of the arrow. Further, the sustaining voltage pulse Vp drops.
Here, due to the two diodes D1 and D2, the resonance current IL does not flow through the body diodes (not shown) of the first high-side main switch element Q1 and the first low-side main switch element Q2.

The sustaining pulse voltage Vp reaches a negative peak value. At the same time, the resonance current IL is attenuated to substantially zero.
At that time, the controller 33 turns off the second low-side main switch element Q4 and the low-side recovery switch element Q6, and turns on the first low-side main switch element Q2 and the second high-side main switch element Q3. Since the current IL is substantially equal to zero in the second low-side main switch element Q4 and the low-side recovery switch element Q6, switching loss does not occur. In the two main switch elements Q2 and Q3, since the voltage between both ends is equal to zero, no switching loss occurs.
Thus, the sustaining voltage pulse Vp is clamped to a negative peak value.
When the discharge is maintained in the PDP 20, power for maintaining the discharge current is supplied from the PFC converter 40 to the PDP 20 through the input terminal 1T and the transformer 2.

When a predetermined time corresponding to the pulse width of the sustaining voltage pulse has elapsed, the control unit 33 further changes the polarity of the sustaining voltage pulse Vp from negative to positive as follows.
The control unit 33 turns off the first low-side main switch element Q2 and turns on the high-side recovery switch element Q5. Since the current is substantially equal to zero in the first low-side main switching device Q2, no switching loss occurs.
By this switching, the loop of the high side recovery switch element Q5 → the inductor L → the primary winding 2a of the transformer 2 → the second high side main switch element Q3 → the high side recovery switch element Q5 becomes conductive (the arrow indicates the direction of the current). (See Figure 21). At that time, the inductor L and the panel capacitance Cp resonate through the transformer 2. The resonance current IL flows through the loop in the direction of the arrow. Furthermore, the sustaining voltage pulse Vp increases.
Here, due to the two diodes D1 and D2, the resonance current IL does not flow through the body diodes (not shown) of the first high-side main switch element Q1 and the first low-side main switch element Q2.

The sustaining pulse voltage Vp reaches a positive peak value. At the same time, the resonance current IL is attenuated to substantially zero.
At that time, the controller 33 turns off the second high-side main switch element Q3 and the high-side recovery switch element Q5, and turns on the first high-side main switch element Q1 and the second low-side main switch element Q4. . Since the current IL is substantially equal to zero in the second high-side main switch element Q3 and the high-side recovery switch element Q5, no switching loss occurs. In the two main switch elements Q1 and Q4, the voltage across the terminals is equal to zero, so that no switching loss occurs.
Thus, the sustaining voltage pulse Vp is clamped to a positive peak value.

When the polarity of the sustaining voltage pulse Vp is reversed, the panel capacitance Cp of the PDP 20 and the inductor L of the power recovery unit 4 resonate as described above. Due to the resonance, the polarity of the sustaining voltage pulse Vp is reversed with little power consumption. As a result, reactive power resulting from charging / discharging of the panel capacitance Cp of the PDP 20 is reduced.
Thus, in the PDP driving apparatus according to the ninth embodiment of the present invention, the power recovery unit 4 functions in the same manner as that according to the fourth embodiment and provides the same effect.

<< Embodiment 10 >>
In the PDP drive device according to the fifth embodiment of the present invention (see FIG. 14), the two power recovery units 4Y and 4X have the same circuit configuration as that according to the ninth embodiment instead of the one shown in FIG. (See Figures 21 and 22). Here, the components other than the power recovery units 4Y and 4X are the same as those according to the fifth embodiment (see FIGS. 14 and 15).
In FIG. 22, the same reference numerals as those shown in FIGS. 15 and 21 are given to the same components as those shown in FIGS. Further, for the details of the similar constituent elements, the descriptions of the fifth and ninth embodiments are incorporated.

The secondary windings 2bY and 2bX of the two transformers 2Y and 2X are connected with their polarities reversed, for example, as shown in FIG. At that time, the control unit 34 (see FIG. 14) maintains the switching operation of the two sustaining pulse generation units 1Y and 1X and the switching operation of the two power recovery units 4Y and 4X in substantially the same phase.
Apart from the example shown in FIG. 22, the secondary windings 2bY and 2bX of the two transformers 2Y and 2X may be connected with the same polarity. At that time, the controller 34 maintains the switching operations of the two sustaining pulse generators 1Y and 1X and the switching operations of the two power recovery units 4Y and 4X in substantially opposite phases.

The switching operations of the two sustaining pulse generating units 1Y and 1X and the two power recovery units 4Y and 4X are the same as the switching operation of the sustaining pulse generating unit 1 and the power recovery unit 4 according to the ninth embodiment, respectively. Therefore, the potential change of the scan electrode Y of the PDP 20 is maintained in the opposite phase to the potential change of the sustain electrode X. Therefore, the sustaining pulse voltage Vp applied between the scan electrode Y and the sustain electrode X is the same as that according to the ninth embodiment.
In particular, the inductor L of the power recovery units 4Y and 4X simultaneously resonates with the panel capacitance Cp of the PDP 20 at every rise / fall of the sustaining voltage pulse Vp. Due to these resonances, power is efficiently exchanged between the inductor L of the power recovery units 4Y and 4X and the panel capacitance Cp. As a result, reactive power due to charging / discharging of the panel capacitance Cp is reduced.

  Separately from the above, the control unit 34 performs the switching operation between the second discharge sustaining pulse generation unit 1X and the second power recovery unit 4X, the first discharge sustaining pulse generation unit 1Y and the first power recovery unit 4Y It may be delayed from the switching operation (see FIG. 16). As a result, the inductor L of the two power recovery units 4Y and 4X alternately resonates with the panel capacitance Cp of the PDP 20 at every rising / falling of the sustaining voltage pulse Vp. Due to these resonances, power is efficiently exchanged between the panel capacitance Cp and the two inductors L. As a result, reactive power resulting from charging / discharging of the panel capacitance Cp is reduced.

  In the PDP driving device according to the tenth embodiment of the present invention, the power recovery units 4Y and 4X function in the same manner as those according to the fifth embodiment as described above, and provide the same effects.

Similarly to the apparatus according to the fifth embodiment, the PDP driving apparatus according to the sixth embodiment of the present invention (see FIG. 17) has two power recovery units 4A and 4B similar to those according to the ninth embodiment instead of the one shown in FIG. (See FIG. 21). Here, the components other than the power recovery units 4A and 4B are the same as those according to the sixth embodiment (see FIGS. 17 and 18).
In particular, the control unit 35 (see FIG. 17) maintains the switching operations of the two discharge sustaining pulse generating units 1A and 1B and the two power recovery units 4A and 4B in the same phase (or opposite phase), respectively. As a result, the two power recovery units 4A and 4B function in the same manner as in the sixth embodiment and provide the same effects.

<< Embodiment 11 >>
In the PDP driving device (see FIG. 12) according to Embodiment 4 of the present invention, the power recovery unit 4 may have the following circuit configuration instead of the one shown in FIG. 13 (see FIG. 23). Here, the components other than the power recovery unit 4 are the same as those according to the fourth embodiment (see FIGS. 12 and 13).
In FIG. 23, constituent elements similar to those shown in FIG. 13 are denoted by the same reference numerals as those shown in FIG. Furthermore, the description about Embodiment 4 is used about the detail of those similar components.

The sustaining pulse generator 1 further includes two diodes D1 and D2.
The anode of the first diode D1 is connected to the first high-side main switch element Q1, and the cathode is connected to the first low-side main switch element Q2.
The anode of the second diode D2 is connected to the second high-side main switch element Q3, and the cathode is connected to the second low-side main switch element Q4.
Between the connection point J1 of the first diode D1 and the first high-side main switch element Q1, and the connection point J2 of the second diode D2 and the second high-side main switch element Q3, The primary winding 2a is connected.

The power recovery unit 4 includes two recovery switch elements Q5 and Q6 and an inductor L.
The two recovery switch elements Q5 and Q6 are preferably MOSFETs. In addition, an IGBT or a bipolar transistor may be used.
The inductor L is preferably an element independent of the transformer 2. In addition, the leakage inductance of the transformer 2 may be used.
The first recovery switch element Q5 and the inductor L are connected in series between one end of the primary winding 2a of the transformer 2 and the ground terminal. The second recovery switch element Q6 is connected between the other end of the primary winding 2a of the transformer 2 and the ground terminal.

The control unit 33 (see FIG. 12) controls the voltage across the panel capacitance Cp, that is, the polarity of the sustaining voltage pulse Vp from the positive as follows by ON / OFF control for the main switch elements Q1 to Q4 and the recovery switch elements Q5 and Q6. Change to negative.
The first high-side main switch element Q1 and the second low-side main switch element Q4 are kept on, and the other switch elements Q2, Q3, Q5, Q6 are kept off. At that time, the potential of the scan electrode Y, that is, the sustaining voltage pulse Vp is maintained at a positive peak value. Here, the peak value is determined by the potential Vs of the input terminal 1T of the sustaining pulse generator 1 and the winding ratio of the transformer 2.
When the discharge is maintained in the PDP 20, power for maintaining the discharge current is supplied from the PFC converter 40 to the PDP 20 through the input terminal 1T and the transformer 2.

When the state is maintained for a predetermined time corresponding to the pulse width of the sustaining voltage pulse, the control unit 33 turns off the first high-side main switch element Q1 and the second low-side main switch element Q4, The two recovery switch elements Q5 and Q6 are both turned on. Since the current is substantially equal to zero in the two main switch elements Q1 and Q4, no switching loss occurs.
By the switching, the loop of the ground terminal ← first recovery switch element Q5 ← inductor L ← primary winding 2a of transformer 2 ← second recovery switch element Q6 ← ground terminal is conducted (the arrow indicates the direction of current). (See Figure 23). At that time, the inductor L and the panel capacitance Cp resonate through the transformer 2. The resonance current IL flows through the loop in the direction of the arrow. Further, the sustaining voltage pulse Vp drops.
Here, due to the two diodes D1 and D2, the resonance current IL does not flow through the body diodes (not shown) of the two low-side main switch elements Q2 and Q4.

The sustaining pulse voltage Vp reaches a negative peak value. At the same time, the resonance current IL is attenuated to substantially zero.
At that time, the controller 33 turns off the two recovery switch elements Q5 and Q6 and turns on the first low-side main switch element Q2 and the second high-side main switch element Q3. Since the current IL is substantially equal to zero in the two recovery switch elements Q5 and Q6, no switching loss occurs. In the two main switch elements Q2 and Q3, since the voltage between both ends is equal to zero, no switching loss occurs.
Thus, the sustaining voltage pulse Vp is clamped to a negative peak value.
When the discharge is maintained in the PDP 20, power for maintaining the discharge current is supplied from the PFC converter 40 to the PDP 20 through the input terminal 1T and the transformer 2.

Similarly, the control unit 33 changes the polarity of the sustaining voltage pulse Vp from negative to positive by on / off control for the main switch elements Q1 to Q4 and the recovery switch elements Q5 and Q6.
When the polarity of the sustaining voltage pulse Vp is reversed, the panel capacitance Cp of the PDP 20 and the inductor L of the power recovery unit 4 resonate as described above. Due to the resonance, the polarity of the sustaining voltage pulse Vp is reversed with little power consumption. As a result, reactive power resulting from charging / discharging of the panel capacitance Cp of the PDP 20 is reduced.
Thus, in the PDP driving apparatus according to the eleventh embodiment of the present invention, the power recovery unit 4 functions in the same manner as that according to the fourth embodiment and provides the same effect.

<< Embodiment 12 >>
In the PDP drive device according to the fifth embodiment of the present invention (see FIG. 14), the two power recovery units 4Y and 4X have the same circuit configuration as that according to the eleventh embodiment, instead of the one shown in FIG. (See Figures 23 and 24). Here, the components other than the power recovery units 4Y and 4X are the same as those according to the fifth embodiment (see FIGS. 14 and 15).
In FIG. 24, the same reference numerals as those shown in FIGS. 15 and 23 are given to the same components as those shown in FIGS. Furthermore, the description about Embodiment 5, 11 is used for the detail of those similar components.

The secondary windings 2bY and 2bX of the two transformers 2Y and 2X are connected with their polarities reversed, for example, as shown in FIG. At that time, the control unit 34 (see FIG. 14) maintains the switching operation of the two sustaining pulse generation units 1Y and 1X and the switching operation of the two power recovery units 4Y and 4X in substantially the same phase.
Apart from the example shown in FIG. 24, the secondary windings 2bY and 2bX of the two transformers 2Y and 2X may be connected with the same polarity. At that time, the controller 34 maintains the switching operations of the two sustaining pulse generators 1Y and 1X and the switching operations of the two power recovery units 4Y and 4X in substantially opposite phases.

The switching operations of the two sustaining pulse generating units 1Y and 1X and the two power recovery units 4Y and 4X are the same as the switching operation of the sustaining pulse generating unit 1 and the power recovery unit 4 according to the eleventh embodiment. Therefore, the potential change of the scan electrode Y of the PDP 20 is maintained in the opposite phase to the potential change of the sustain electrode X. Therefore, the sustaining pulse voltage Vp applied between the scan electrode Y and the sustain electrode X is the same as that according to the eleventh embodiment.
In particular, the inductor L of the power recovery units 4Y and 4X simultaneously resonates with the panel capacitance Cp of the PDP 20 at every rise / fall of the sustaining voltage pulse Vp. Due to these resonances, power is efficiently exchanged between the inductor L of the power recovery units 4Y and 4X and the panel capacitance Cp. As a result, reactive power due to charging / discharging of the panel capacitance Cp is reduced.

  Separately from the above, the control unit 34 performs the switching operation between the second discharge sustaining pulse generation unit 1X and the second power recovery unit 4X, the first discharge sustaining pulse generation unit 1Y and the first power recovery unit 4Y It may be delayed from the switching operation (see FIG. 16). As a result, the inductor L of the two power recovery units 4Y and 4X alternately resonates with the panel capacitance Cp of the PDP 20 at every rising / falling of the sustaining voltage pulse Vp. Due to these resonances, power is efficiently exchanged between the panel capacitance Cp and the two inductors L. As a result, reactive power resulting from charging / discharging of the panel capacitance Cp is reduced.

  In the PDP driving device according to the twelfth embodiment of the present invention, the power recovery units 4Y and 4X function in the same manner as those according to the fifth embodiment as described above, and provide the same effects.

Similarly to the apparatus according to the fifth embodiment, the PDP driving apparatus according to the sixth embodiment of the present invention (see FIG. 17) is similar to the apparatus according to the eleventh embodiment, except that the two power recovery units 4A and 4B are shown in FIG. (See FIG. 23). Here, the components other than the power recovery units 4A and 4B are the same as those according to the sixth embodiment (see FIGS. 17 and 18).
In particular, the control unit 35 (see FIG. 17) maintains the switching operations of the two discharge sustaining pulse generating units 1A and 1B and the two power recovery units 4A and 4B in the same phase (or opposite phase), respectively. As a result, the two power recovery units 4A and 4B function in the same manner as in the sixth embodiment and provide the same effects.

<< Embodiment 13 >>
In the PDP driving device according to the eleventh embodiment of the present invention, one ends of the two recovery switch elements Q5 and Q6 of the power recovery unit 4 are grounded (see FIG. 23). In addition, one end of the two recovery switch elements Q5 and Q6 may be connected to the input terminal 1T (see FIG. 25).
At that time, between the connection point J1 of the first diode D1 and the first low-side main switch element Q2 and the connection point J2 of the second diode D2 and the second low-side main switch element Q4, the transformer 2 Primary winding 2a is connected. The resonance current IL does not flow through the body diodes (not shown) of the two high-side main switch elements Q1 and Q3 due to the two diodes D1 and D2.
In FIG. 25, the same components as those shown in FIG. 23 are denoted by the same reference numerals as those shown in FIG. Furthermore, the description about Embodiment 4 or 11 is used about the detail of those similar components.

The control unit 33 (see FIG. 12) controls the switching operation of the discharge sustaining pulse generating unit 1 and the power recovery unit 4 in exactly the same manner as in the eleventh embodiment. Thereby, when the polarity of the sustaining voltage pulse Vp is inverted, the panel capacitance Cp of the PDP 20 and the inductor L of the power recovery unit 4 resonate. Due to the resonance, the polarity of the sustaining voltage pulse Vp is reversed with little power consumption. As a result, reactive power resulting from charging / discharging of the panel capacitance Cp of the PDP 20 is reduced.
Thus, in the PDP driving apparatus according to the thirteenth embodiment of the present invention, the power recovery unit 4 functions in the same manner as that according to the fourth embodiment and provides the same effect.

<< Embodiment 14 >>
In the PDP driving device (see FIG. 14) according to the fifth embodiment of the present invention, the two power recovery units 4Y and 4X have the same circuit configuration as that according to the thirteenth embodiment, instead of the one shown in FIG. (See Figures 25 and 26). Here, the components other than the power recovery units 4Y and 4X are the same as those according to the fifth embodiment (see FIGS. 14 and 15).
In FIG. 26, the same reference numerals as those shown in FIGS. 15 and 25 are given to the same components as those shown in FIGS. Furthermore, the description about Embodiment 5 and 13 is used for the detail of those similar components.

The secondary windings 2bY and 2bX of the two transformers 2Y and 2X are connected with their polarities reversed, for example, as shown in FIG. At that time, the control unit 34 (see FIG. 14) maintains the switching operation of the two sustaining pulse generation units 1Y and 1X and the switching operation of the two power recovery units 4Y and 4X in substantially the same phase.
Apart from the example shown in FIG. 26, the secondary windings 2bY and 2bX of the two transformers 2Y and 2X may be connected with the same polarity. At that time, the controller 34 maintains the switching operations of the two sustaining pulse generators 1Y and 1X and the switching operations of the two power recovery units 4Y and 4X in substantially opposite phases.

The switching operations of the two sustaining pulse generating units 1Y and 1X and the two power recovery units 4Y and 4X are the same as the switching operations of the sustaining pulse generating unit 1 and the power recovery unit 4 according to the thirteenth embodiment, respectively. Therefore, the potential change of the scan electrode Y of the PDP 20 is maintained in the opposite phase to the potential change of the sustain electrode X. Therefore, the sustaining pulse voltage Vp applied between the scan electrode Y and the sustain electrode X is the same as that according to the thirteenth embodiment.
In particular, the inductor L of the power recovery units 4Y and 4X simultaneously resonates with the panel capacitance Cp of the PDP 20 at every rise / fall of the sustaining voltage pulse Vp. Due to these resonances, power is efficiently exchanged between the inductor L of the power recovery units 4Y and 4X and the panel capacitance Cp. As a result, reactive power due to charging / discharging of the panel capacitance Cp is reduced.

  Separately from the above, the control unit 34 performs the switching operation between the second discharge sustaining pulse generation unit 1X and the second power recovery unit 4X, the first discharge sustaining pulse generation unit 1Y and the first power recovery unit 4Y It may be delayed from the switching operation (see FIG. 16). As a result, the inductor L of the two power recovery units 4Y and 4X alternately resonates with the panel capacitance Cp of the PDP 20 at every rising / falling of the sustaining voltage pulse Vp. Due to these resonances, power is efficiently exchanged between the panel capacitance Cp and the two inductors L. As a result, reactive power resulting from charging / discharging of the panel capacitance Cp is reduced.

  In the PDP driving device according to the fourteenth embodiment of the present invention, the power recovery units 4Y and 4X function in the same manner as those according to the fifth embodiment as described above, and provide the same effects.

Similarly to the apparatus according to the fifth embodiment, the PDP driving apparatus according to the sixth embodiment of the present invention (see FIG. 17) is similar to the apparatus according to the thirteenth embodiment except that two power recovery units 4A and 4B are replaced with those shown in FIG. (See FIG. 25). Here, the components other than the power recovery units 4A and 4B are the same as those according to the sixth embodiment (see FIGS. 17 and 18).
In particular, the control unit 35 (see FIG. 17) maintains the switching operations of the two discharge sustaining pulse generating units 1A and 1B and the two power recovery units 4A and 4B in the same phase (or opposite phase), respectively. As a result, the two power recovery units 4A and 4B function in the same manner as in the sixth embodiment and provide the same effects.

<< Embodiment 15 >>
The PDP driving devices according to Embodiments 5, 8, 10, 12, and 14 of the present invention have a common circuit configuration except for the specific circuit configuration of the two power recovery units 4Y and 4X (see FIG. 14). In particular, the secondary windings 2bY, 2bX of the two transformers 2Y, 2X and the panel capacitance Cp of the PDP 20 are connected in series (see FIGS. 15, 20, 22, 24, 26). In this configuration, for example, one drive unit may not include the power recovery unit as follows (see FIG. 27). Thereby, the number of parts is reduced and the mounting area is reduced.
The first drive unit 10Y includes a power recovery unit 4 on the primary side of the first transformer 2Y. On the other hand, the second drive unit 10X does not include a power recovery unit.
The circuit configuration of the power recovery unit 4 is the same as that of the power recovery unit according to the fourth embodiment, for example (see FIG. 15). In addition, it may be the same as the power recovery unit according to the seventh, ninth, eleventh, or twelfth embodiment.
In FIG. 27, the same components as those shown in FIG. 15 are denoted by the same reference numerals as those shown in FIG. Furthermore, the description about Embodiment 4 is used about the detail of those similar components.

The control unit 34 (see FIG. 14) sets the following phase difference (greater than 0 ° and smaller than 180 °) between the switching operations of the two discharge sustain pulse generating units 1Y and 1X.
For example, it is assumed that the secondary windings 2bY and 2bX of the two transformers 2Y and 2X are connected with opposite polarities (see FIG. 27).
Here, the secondary windings 2bY and 2bX of the two transformers 2Y and 2X may be connected with the same polarity. At that time, the control unit 34 controls the switching operation of one of the drive units to have a substantially opposite phase to the following switching operation.

  The first high-side main switch element Q1 and the second low-side main switch element Q4 remain on in both of the two sustaining pulse generators 1Y and 1X, and the other switch elements Q2, Q3, Q5, and Q6 Remains off. At that time, the potential of the scan electrode Y is maintained at a positive peak value, and the potential of the sustain electrode X is maintained at a negative peak value. Accordingly, the sustaining voltage pulse Vp is maintained at a positive peak value.

When the state is maintained for a predetermined time corresponding to the pulse width of the sustaining voltage pulse, the control unit 34, for the first sustaining pulse generation unit 1Y, the first high-side main switch element Q1 and the second The low-side main switch element Q4 is turned off, and the first recovery switch element Q5 is turned on. At that time, since the current is substantially equal to zero in the first sustaining pulse generator 1Y, no switching loss occurs.
On the other hand, for the second sustaining pulse generator 1X, the on / off states of the four main switch elements Q1 to Q4 are maintained as they are.
Due to the switching, the inductor L of the power recovery unit 4 resonates with the panel capacitance Cp of the PDP 20. Since the resonance current IL flows through the inductor L and the potential of the scan electrode Y falls from the positive peak value, the sustaining voltage pulse Vp falls from the positive peak value.

When the potential of the scan electrode Y reaches a negative peak value, the sustaining voltage pulse Vp reaches zero. At that time, the controller 34 turns off the first high-side main switch element Q1 and the second low-side main switch element Q4 for the second sustaining pulse generator 1X. In the second sustaining pulse generator 1X, since the current is substantially equal to zero, no switching loss occurs.
Subsequently, the control unit 34 turns on the first low-side main switch element Q2 and the second high-side main switch element Q3 for the second discharge sustaining pulse generation unit 1X. On the other hand, the main switch elements Q1 to Q4 are maintained in the off state for the first sustaining pulse generation unit 1Y, and the on / off states of the recovery switch elements Q5 and Q6 are maintained as they are for the power recovery unit 4.
By the switching, the inductor L of the power recovery unit 4 further resonates with the panel capacitance Cp. The resonance current IL further flows through the inductor L, and the potential of the scan electrode Y further decreases.
Thus, the polarity of the sustaining voltage pulse Vp changes from positive to negative.

When the potential of the scan electrode Y reaches a negative peak value, the sustaining voltage pulse Vp reaches a negative peak value. At the same time, the resonance current IL is attenuated to substantially zero, so that the second diode D2 is turned off in the power recovery unit 4. At that time, the controller 34 turns off the first recovery switch element Q5. Here, since the resonance current IL is substantially equal to zero, no switching loss occurs.
Further, the control unit 34 turns on the first low-side main switch element Q2 and the second high-side main switch element Q3 for the first discharge sustaining pulse generation unit 1Y. In these main switch elements Q2 and Q3, the voltage across the terminals is substantially equal to zero, so that no switching loss occurs.
As a result of the switching, the potential of the scan electrode Y is clamped to a negative peak value, so that the sustaining voltage pulse Vp is clamped to a negative peak value.

Similarly, when the polarity of the sustaining voltage pulse Vp is changed from negative to positive, the control unit 34 provides a phase difference between the switching operations of the two sustaining pulse generators 1Y and 1X.
In this way, the inductor L of the single power recovery unit 4 resonates with the panel capacitance Cp of the PDP 20 every time the discharge sustaining pulse voltage Vp rises / falls. Due to the resonance, power is efficiently exchanged between the panel capacitance Cp and the inductor L. As a result, reactive power due to charging / discharging of the panel capacitance Cp is reduced.

  In the PDP driving device according to the fifteenth embodiment of the present invention, the single power recovery unit 4 functions in the same manner as the two power recovery units 4Y and 4X according to the fifth embodiment as described above, and provides the same effect.

Embodiment 16
The PDP driving devices according to Embodiments 5, 8, 10, 12, and 14 of the present invention have a common circuit configuration except for the specific circuit configuration of the two power recovery units 4Y and 4X (see FIG. 14). In particular, the secondary windings 2bY, 2bX of the two transformers 2Y, 2X and the panel capacitance Cp of the PDP 20 are connected in series (see FIGS. 15, 20, 22, 24, 26). Furthermore, each of the power recovery units 4Y and 4X includes two recovery switch elements Q5 and Q6 to constitute a bidirectional switch.
In this configuration, for example, as described below, the power recovery unit may include only a unidirectional switch so that only one-way current flows through the inductor L (see FIG. 28). Thereby, the number of parts is reduced and the mounting area is reduced.

The power recovery units 41Y and 41X are the same as those obtained by replacing the bidirectional switches Q5, Q6, D1, and D2 included in the power recovery unit 4 according to the fourth embodiment with unidirectional switches Q5 and D1, for example (see FIG. 15). ). That is, each power recovery unit 41Y, 41X includes only one set of parallel connection of recovery switch element Q5 and diode D1. The parallel connection is connected in series with the inductor L. Thereby, the recovery switch element Q5 can cut off only the current in the reverse bias direction of the diode D1.
In addition, the two power recovery units 41Y and 41X may be the same as those obtained by replacing the bidirectional switch with a unidirectional switch in the power recovery unit according to the seventh, ninth, eleventh, or twelfth embodiment.
In FIG. 28, constituent elements similar to those shown in FIG. 15 are assigned the same reference numerals as those shown in FIG. Furthermore, the description about Embodiment 4 is used about the detail of those similar components.

The control unit 34 (see FIG. 14) has the following phase difference (greater than 0 ° and smaller than 180 °) between the switching operations of the two sustaining pulse generation units 1Y and 1X and the two power recovery units 41Y and 41X. Set.
For example, it is assumed that the secondary windings 2bY and 2bX of the two transformers 2Y and 2X are connected with the same polarity (see FIG. 28). At that time, the diode D1 is connected with the same polarity in the two power recovery units 41Y and 41X. Further, the control unit 34 performs the switching operation of the two sustaining pulse generating units 1Y and 1X in substantially the same phase.
The secondary windings 2bY and 2bX of the two transformers 2Y and 2X may be connected with their polarities reversed. At that time, the polarity of the diode D1 is reversed between the two power recovery units 41Y and 41X. Further, the control unit 31 performs switching operations of the two sustaining pulse generation units 1Y and 1X in substantially opposite phases.

In the first sustaining pulse generator 1Y, the first high-side main switch element Q1 and the second low-side main switch element Q4 are kept on, and the other switch elements Q2, Q3, Q5 are turned off. maintain. At that time, the potential of the scan electrode Y is maintained at a positive peak value.
In the second sustaining pulse generator 1X, the first low-side main switch element Q2 and the second high-side main switch element Q3 are kept on, and the other switch elements Q1, Q4, Q5 are turned off. maintain. At that time, the potential of the sustain electrode X is maintained at a negative peak value.
Accordingly, the sustaining voltage pulse Vp is maintained at a positive peak value.

When the state is maintained for a predetermined time corresponding to the pulse width of the discharge sustaining pulse voltage, the control unit 34, for the first discharge sustaining pulse generating unit 1Y, the first high-side main switch element Q1 and the second The low side main switch element Q4 is turned off. At that time, since the current is substantially equal to zero in the first sustaining pulse generator 1Y, no switching loss occurs. Further, the control unit 34 turns on the recovery switch element Q5 for the first power recovery unit 41Y.
On the other hand, for the second sustaining pulse generator 1X and the second power recovery unit 41X, the on / off states of the main switch elements Q1 to Q4 and the recovery switch element Q5 are maintained as they are.
Due to the switching, the inductor L of the first power recovery unit 41Y resonates with the panel capacitance Cp of the PDP 20. Since the resonance current IL flows through the inductor L and the potential of the scan electrode Y falls from the positive peak value, the sustaining voltage pulse Vp falls from the positive peak value.

When the potential of the scan electrode Y reaches a negative peak value, the sustaining voltage pulse Vp reaches zero. At that time, the control unit 34 turns off the first low-side main switching device Q2 and the second high-side main switching device Q3 for the second discharge sustaining pulse generating unit 1X. In the second sustaining pulse generator 1X, since the current is substantially equal to zero, no switching loss occurs.
Subsequently, the control unit 34 turns on the first high-side main switch element Q1 and the second low-side main switch element Q4 for the second discharge sustaining pulse generation unit 1X. On the other hand, the main switch elements Q1 to Q4 are maintained in the OFF state for the first discharge sustaining pulse generating unit 1Y, and the recovery switch element Q5 is maintained in the ON state for the first power recovery unit 41Y.
By the switching, the inductor L of the first power recovery unit 41Y further resonates with the panel capacitance Cp. The resonance current IL further flows through the inductor L in the same direction, and the potential of the scan electrode Y further decreases.
Thus, the polarity of the sustaining voltage pulse Vp changes from positive to negative.

When the potential of the scan electrode Y reaches a negative peak value, the sustaining voltage pulse Vp reaches a negative peak value. At the same time, the resonance current IL is attenuated to substantially zero. At that time, the control unit 34 turns off the first recovery switch element Q5 for the first power recovery unit 41Y. Here, since the resonance current IL is substantially equal to zero, no switching loss occurs.
Further, the control unit 34 turns on the first low-side main switch element Q2 and the second high-side main switch element Q3 for the first discharge sustaining pulse generation unit 1Y. In these main switch elements Q2 and Q3, the voltage across the terminals is substantially equal to zero, so that no switching loss occurs.
As a result of the switching, the potential of the scan electrode Y is clamped to a negative peak value, so that the sustaining voltage pulse Vp is clamped to a negative peak value.

Similarly, when the polarity of the sustaining voltage pulse Vp is changed from negative to positive, the control unit 34 provides a phase difference between the switching operations of the two sustaining pulse generators 1Y and 1X.
Thus, the inductor L of the two power recovery units 41Y and 41X alternately resonates with the panel capacitance Cp of the PDP 20 at every rising / falling of the sustaining voltage pulse Vp. Due to these resonances, power is efficiently exchanged between the panel capacitance Cp and the inductor L. As a result, reactive power due to charging / discharging of the panel capacitance Cp is reduced.
Particularly in those resonances, the resonance current IL flows through the inductor L only in one direction.

  In the PDP driving device according to the sixteenth embodiment of the present invention, the two power recovery units 41Y and 41X function in the same manner as the two power recovery units 4Y and 4X according to the fifth embodiment as described above, and provide the same effects.

<< Embodiment 17 >>
In the plasma display according to the seventeenth embodiment of the present invention, unlike the plasma display according to the fourth embodiment, the PDP driving device 10 includes the power recovery unit 5 on the secondary side of the transformer 2 (see FIG. 29). Other than that, the configuration of both plasma displays is the same (see FIG. 12).
In FIG. 29, the same reference numerals as those shown in FIG. 12 are given to the same constituent elements as those shown in FIG. Furthermore, the description about Embodiment 1 and 4 is used about the detail of those similar components.

  The power recovery unit 5 is connected to the secondary winding 2b of the transformer 2, and includes an inverter and a switch unit. For example, the switch unit is turned on each time the primary pulse voltage VF from the sustaining pulse generating unit 1 or the secondary pulse voltage Vp from the transformer 2 corresponding thereto rises / falls, and the inverter is turned on by the scan electrode (or sustain electrode) of the PDP 20. ). The inverter then resonates with the panel capacity of the PDP 20.

Similarly to the control unit 33 according to the fourth embodiment, the control unit 36 controls switching of the discharge sustain pulse generating unit 1, the initialization / scanning pulse generating unit 3, and the address electrode driving unit (not shown) according to the ADS method.
The control unit 36 further controls the switching operation of the power recovery unit 5 during the discharge sustaining period, and synchronizes with the switching operation of the discharge sustaining pulse generating unit 1.

FIG. 30 is an equivalent circuit diagram of the sustaining pulse generating unit 1, the transformer 2, the power recovery unit 5, and the PDP 20.
The circuit configuration of the power recovery unit 5 is exactly the same as the circuit configuration of the power recovery unit 4 according to the fourth embodiment (see FIG. 13). However, the series connection of the two recovery switch elements Q5 and Q6 and the inductor L is connected in parallel with the secondary winding 2b of the transformer 2. Furthermore, the inductance of the inductor L is preferably sufficiently smaller than the excitation inductance of the transformer 2.
In FIG. 30, the same components as those shown in FIG. 13 are denoted by the same reference numerals as those shown in FIG. Furthermore, the description about Embodiment 1 and 4 is used for the detail of those similar components.

  The control unit 36 (see FIG. 29) performs on / off control on the main switch elements Q1 to Q4 and the recovery switch elements Q5 and Q6, just like the control unit 33 (see FIG. 12) according to the fourth embodiment. Accordingly, every time the polarity of the sustaining voltage pulse Vp is inverted, the panel capacitance Cp of the PDP 20 and the inductor L of the power recovery unit 5 resonate. Due to the resonance, the polarity of the sustaining voltage pulse Vp is reversed with little power consumption. As a result, reactive power due to charging / discharging of the panel capacitance Cp of the PDP 20 is reduced.

  The PDP driving apparatus according to the seventeenth embodiment of the present invention has a transformer 2 on the output side of the discharge sustaining pulse generator 1 as in the apparatus according to the first embodiment. The transformer 2 gives the same effect as the transformer 2 according to the first embodiment.

  In the PDP driving device according to the seventeenth embodiment of the present invention, as in the device according to the fourth embodiment, the power recovery unit reduces reactive power due to charging / discharging of the panel capacity. In particular, the resonance period of the inductor L and the panel capacitance Cp is reliably limited to the rising period and the falling period of the sustaining voltage pulse Vp.

In the PDP driving device according to the seventeenth embodiment of the present invention, unlike the device according to the fourth embodiment, the current accompanying the resonance is not substantially upstream to the secondary winding 2b of the transformer 2. Accordingly, no copper loss occurs in the transformer 2 during the resonance period.
Furthermore, since the effective value of the current flowing through the transformer 2 is reduced, the current capacity between the circuit element of the sustaining pulse generating unit 1 and the transformer 2 may be small.
In addition, the iron loss is reduced by reducing the size of the transformer 2. In addition, the breakdown voltage of the recovery switch elements Q5 and Q6 is reduced.

<< Embodiment 18 >>
In the plasma display according to Embodiment 18 of the present invention, unlike the plasma display according to Embodiment 5, each drive unit 10Y, 10X includes power recovery units 5Y, 5X on the secondary side of the transformers 2Y, 2X (see FIG. 31). Other than that, the configuration of both plasma displays is the same (see FIG. 14).
In FIG. 31, the same components as those shown in FIG. 14 are denoted by the same reference numerals as those shown in FIG. Furthermore, the description about Embodiment 5 is used about the detail of those similar components.

In each of the drive units 10Y and 10X, the configuration of the discharge sustain pulse generators 1Y and 1X, the transformers 2Y and 2X, and the power recovery units 5Y and 5X is the same as the discharge sustain pulse generator 1, the transformer 2 and the power recovery according to the seventeenth embodiment. The configuration is the same as that of the unit 5 (see FIGS. 29 to 32). In particular, the characteristics of the circuit elements corresponding to each other are substantially equal.
In FIG. 32, the same reference numerals as those shown in FIG. 30 are given to the same constituent elements as those shown in FIG. Furthermore, the description about Embodiment 5 and 17 is used for the detail of those similar components.

The initialization / scanning pulse generator 3Y has a common circuit configuration with the initialization / scanning pulse generator 3 according to the first embodiment (see FIGS. 3 and 4). Therefore, for the details, FIG. 3, FIG. 4 and the description of Embodiment 1 are incorporated.
The initialization generating unit 3X has a common circuit configuration with the initialization generating unit 3X according to the second embodiment (see FIG. 7). Therefore, for the details, FIG. 7 and the description of Embodiment 2 are incorporated.

Similarly to the control unit 34 (see FIG. 14) according to the fifth embodiment, the control unit 37 (see FIG. 31) includes two discharge sustain pulse generation units 1Y and 1X, an initialization / scanning pulse generation unit 3Y, and an initialization pulse generation unit 3X. , And the address electrode driver (not shown) are controlled according to the ADS method.
The control unit 37 performs on / off control on the main switch elements Q1 to Q4 and the recovery switch elements Q5 and Q6 in the same manner as the control unit 34 according to the fifth embodiment, particularly during the discharge sustain period. Accordingly, the inductor L of the two power recovery units 5Y and 5X resonates with the panel capacitance Cp of the PDP 20 every time the discharge sustaining pulse voltage Vp rises / falls.
When the switching operation of the two discharge sustaining pulse generators 1Y and 1X and the two power recovery units 5Y and 5X is maintained in the same phase (or opposite phase), the inductors L of the two power recovery units 5Y and 5X are simultaneously Resonates with the panel capacitance Cp of the PDP 20.
When a predetermined phase difference (greater than 0 ° and smaller than 180 °) is provided between the switching operations of the two discharge sustaining pulse generators 1Y and 1X and the two power recovery units 5Y and 5X, the two power recovery units 5Y , 5X inductors L alternately resonate with the panel capacitance Cp of the PDP 20 (see FIG. 16).
In any resonance, the polarity of the sustaining voltage pulse Vp is reversed with almost no power consumption. As a result, reactive power resulting from charging / discharging of the panel capacitance Cp of the PDP 20 is reduced.

  The PDP driving apparatus according to the eighteenth embodiment of the present invention has transformers 2Y and 2X on the output side of the discharge sustaining pulse generating units 1Y and 1X, as in the apparatus according to the first embodiment. Each transformer 2Y, 2X gives the same effect as the transformer 2 according to the first embodiment.

  In the PDP driving apparatus according to the eighteenth embodiment of the present invention, as in the apparatus according to the fifth embodiment, reactive power due to charging / discharging of the panel capacity is reduced by the two power recovery units. In particular, the resonance period of the inductor L and the panel capacitance Cp is reliably limited to the rising period and the falling period of the sustaining voltage pulse Vp.

Unlike the apparatus according to the fifth embodiment, the PDP driving apparatus according to the eighteenth embodiment of the present invention maintains the switching operation of the discharge sustain pulse generating units 1Y and 1X and the power recovery units 5Y and 5X in the same phase (or opposite phase). When this occurs, the current associated with the resonance is not substantially upstream of any of the secondary windings 2bY and 2bX of the two transformers 2Y and 2X. Therefore, copper loss does not occur in both transformers 2Y and 2X during the resonance period.
Furthermore, since the effective value of the current flowing through each of the transformers 2Y and 2X is reduced, the current capacity between the circuit elements of the sustaining pulse generating units 1Y and 1X and the transformers 2Y and 2X may be small.
In addition, the transformer 2Y and 2X are reduced in size to reduce the iron loss. In addition, the breakdown voltage of the recovery switch elements Q5 and Q6 is reduced.

Embodiment 19
In the plasma display according to the nineteenth embodiment of the present invention, unlike the plasma display according to the sixth embodiment, the drive units 10A and 10B include the power recovery units 5A and 5B on the secondary side of the transformers 2A and 2B (see FIG. 33). Here, one of the two power recovery units 5A and 5B may be omitted. The configuration of both plasma displays is the same except for the connection position of the power recovery unit (see FIG. 17).
In FIG. 33, the same reference numerals as those shown in FIG. 17 are given to the same constituent elements as those shown in FIG. Furthermore, the description about Embodiment 6 is used for details of similar components.

In each drive unit 10A, 10B, the configuration of the discharge sustain pulse generators 1A, 1B, the transformers 2A, 2B, and the power recovery units 5A, 5B is the same as that of the discharge sustain pulse generator 1, the transformer 2, and the power recovery according to the seventeenth embodiment. The configuration is the same as that of the unit 5 (see FIGS. 29, 30, 33, and 34). In particular, the characteristics of the circuit elements corresponding to each other are substantially equal.
34, the same reference numerals as those shown in FIG. 30 are given to the same components as those shown in FIG. Further, for the details of the similar components, the description of Embodiments 6 and 17 is incorporated.

  The initialization / scanning pulse generation unit 3 has a common circuit configuration with the initialization / scanning pulse generation unit 3 according to the first embodiment (see FIGS. 3 and 4). Therefore, for the details, FIG. 3, FIG. 4 and the description of Embodiment 1 are incorporated.

Similarly to the control unit 35 (see FIG. 17) according to the sixth embodiment, the control unit 38 (see FIG. 33) includes two discharge sustain pulse generating units 1A and 1B, an initialization / scanning pulse generating unit 3, and an address electrode driving unit ( Each switching is controlled according to the ADS system.
The control unit 38 performs on / off control on the main switch elements Q1 to Q4 and the recovery switch elements Q5 and Q6 in the same manner as the control unit 35 according to the sixth embodiment, particularly during the discharge sustain period. In particular, the switching operations of the two discharge sustaining pulse generating units 1A and 1B and the two power recovery units 5A and 5B are maintained in the same phase (or opposite phase). Thereby, every time the discharge sustaining pulse voltage Vp rises / falls, the inductors L of the two power recovery units 5A and 5B simultaneously resonate with the panel capacitance Cp of the PDP 20. Due to the resonance, the polarity of the sustaining voltage pulse Vp is reversed with little power consumption. As a result, reactive power resulting from charging / discharging of the panel capacitance Cp of the PDP 20 is reduced.

  The PDP driving apparatus according to the nineteenth embodiment of the present invention has transformers 2A and 2B on the output side of the discharge sustaining pulse generators 1A and 1B, as in the apparatus according to the first embodiment. Each transformer 2A, 2B gives the same effect as the transformer 2 according to the first embodiment.

  In the PDP driving device according to the nineteenth embodiment of the present invention, as in the device according to the sixth embodiment, the reactive power due to charging / discharging of the panel capacity is reduced by the two power recovery units. In particular, the resonance period of the inductor L and the panel capacitance Cp is reliably limited to the rising period and the falling period of the sustaining voltage pulse Vp.

In the PDP driving device according to the nineteenth embodiment of the present invention, unlike the device according to the sixth embodiment, the current accompanying the resonance does not substantially flow upstream of any of the secondary windings 2bA and 2bB of the two transformers 2A and 2B. The same applies when either one of the two power recovery units 5A and 5B is omitted (because the inductance of the inductor L is sufficiently smaller than the excitation inductance of each transformer 2A and 2B). Therefore, copper loss does not occur in both transformers 2A and 2B during the resonance period.
Further, since the effective value of the current flowing through each of the transformers 2A and 2B is reduced, the current capacity between the circuit elements of the sustaining pulse generating units 1A and 1B and the transformers 2A and 2B may be small.
In addition, the iron loss is reduced by downsizing the transformers 2A and 2B. In addition, the breakdown voltage of the recovery switch elements Q5 and Q6 is reduced.

<< Embodiment 20 >>
In the plasma display according to the twentieth embodiment of the present invention, like the plasma display according to the seventeenth embodiment, the PDP driving apparatus 10 includes two power recovery units 5Y and 5X on the secondary side of the transformer 2 (see FIG. 35). Except for the circuit configurations of the power recovery units 5Y and 5X, the configurations of both plasma displays are the same (see FIG. 29).
Similarly to the control unit 36 according to the seventeenth embodiment, the control unit 36A controls switching of each of the sustaining pulse generating unit 1, the initialization / scanning pulse generating unit 3, and the address electrode driving unit (not shown) according to the ADS method.
In FIG. 35, constituent elements similar to those shown in FIG. 29 are denoted by the same reference numerals as those shown in FIG. Furthermore, the description about Embodiment 1 and 4 is used about the detail of those similar components.

Each of the power recovery units 5Y and 5X has a circuit configuration similar to that of the power recovery units 4a and 4b according to the seventh embodiment (see FIGS. 19 and 36).
In FIG. 36, the same components as those shown in FIG. 19 are denoted by the same reference numerals as those shown in FIG. Furthermore, the description about Embodiment 1 and 7 is used for the detail of those similar components.

In the first power recovery unit 5Y, one end J4 of the inductor L is connected through the initialization / scanning pulse generation unit 3 to the scan electrodes Y1, Y2, Y3,.
In the second power recovery unit 5X, one end J4 of the inductor L is connected to the sustain electrodes X1, X2, X3,.
One end of the secondary winding 2b of the transformer 2 is connected to the scan electrodes Y1, Y2, Y3,... Of the PDP 20 through the first power recovery unit 5Y and the initialization / scanning pulse generation unit 3, and the other end is grounded. . In addition, one end of the secondary winding 2b of the transformer 2 may be connected to the sustain electrodes X1, X2, X3,... Of the PDP 20 through the separation switch and the second power recovery unit 5X, and the other end may be grounded.

In the power recovery units 5Y and 5X, unlike the power recovery units 4a and 4b according to the seventh embodiment, the voltage across the capacitor C is maintained substantially equal to half Vt / 2 of the peak value Vt of the sustaining voltage pulse Vp. (See Figures 19 and 36). Here, the peak value Vt is determined by the potential Vs of the input terminal 1T of the sustaining pulse generator 1 and the winding ratio of the transformer 2.
Further, the ground switch element Q7 is connected between the connection point J4 between the inductor L and the scan electrode Y (or the sustain electrode X) of the PDP 20 and the ground terminal. Here, as the ground conductor, a ground conductor connected to the capacitor C, for example, a frame of the PDP 20 is used.

The control unit 36A controls the switching operation of the power recovery units 5Y and 5X in the same manner as the control unit 33 (see FIG. 12) according to the seventh embodiment during the discharge sustain period. That is, the control unit 36A changes the polarity of the sustaining voltage pulse Vp from positive to negative by the on / off control for the main switch elements Q1 to Q4, the recovery switch elements Q5 and Q6, and the ground switch element Q7 as follows.
When the first high-side main switch element Q1 and the second low-side main switch element Q4 are kept on, the ground switch element Q7 is kept on in the second power recovery unit 5X (other main switches The elements Q2, Q3, the recovery switch elements Q5, Q6, and the other ground switch element Q7 remain off). Thereby, the potential of the scan electrode Y, that is, the sustaining voltage pulse Vp is maintained at the positive peak value Vt (sustain electrode X is maintained at the ground voltage).
When the discharge is maintained in the PDP 20, power for maintaining the discharge current is supplied from the PFC converter 40 to the PDP 20 through the input terminal 1T and the transformer 2.

When the state is maintained for a predetermined time corresponding to the pulse width of the sustaining voltage pulse, the control unit 36A turns off the first high-side main switch element Q1 and the second low-side main switch element Q4, The low-side recovery switch element Q6 is turned on by one power recovery unit 5Y. Since the current is substantially equal to zero in the two main switch elements Q1 and Q4, no switching loss occurs.
In the first power recovery unit 5Y, the path of the scanning electrode Y of the ground terminal ← capacitor C ← low side recovery switch element Q6 ← low side diode D2 ← inductor L ← PDP 20 is conducted (the arrow indicates the direction of current). 36). Here, the initialization / scanning pulse generator 3 short-circuits between the input terminal 3A and the output terminal 3B. On the other hand, the sustain electrode X of the PDP 20 is grounded through the ground switch element Q7 of the second power recovery unit 5X. Therefore, the voltage Vt / 2 across the capacitor C is applied to the panel capacitance Cp of the PDP 20. At that time, the inductor L and the panel capacitance Cp resonate. The resonance current IL flows through the above path in the direction of the arrow, and the panel capacitance Cp is discharged. As a result, the potential of the scan electrode Y, that is, the sustaining voltage pulse Vp drops.

When the resonance current IL is attenuated to substantially zero, the low-side diode D2 is turned off. At the same time, the sustaining voltage pulse Vp reaches zero. At that time, the controller 36A turns off the low-side recovery switch element Q6 and turns on the ground switch element Q7. Since the voltage across the ground switch element Q7 is equal to zero, no switching loss occurs.
Thus, the sustaining voltage pulse Vp is clamped to zero.

Subsequently, the control unit 36A turns off the ground switch element Q7 and turns on the high-side recovery switch element Q5 for the second power recovery unit 5X. Since the voltage across the ground switch element Q7 is equal to zero, no switching loss occurs.
At that time, in the second power recovery unit 5X, the sustain electrode X of the PDP 20 ← inductor L ← high side diode D1 ← high side recovery switch element Q5 ← capacitor C ← ground terminal path is conducted (the arrow indicates the direction of current) (See FIG. 36). On the other hand, the scan electrode Y of the PDP 20 is grounded through the ground switch element Q7 of the first power recovery unit 5Y. Therefore, the voltage Vt / 2 across the capacitor C is applied to the panel capacitance Cp of the PDP 20. At that time, the inductor L and the panel capacitance Cp resonate. The resonance current IL flows through the above path in the direction of the arrow, and the panel capacitance Cp is charged. As a result, the potential of the sustain electrode X increases and the sustaining voltage pulse Vp decreases.

When the resonance current IL is attenuated to substantially zero, the high-side diode D1 is turned off. At the same time, the sustaining voltage pulse Vp reaches a negative peak value −Vt. At that time, the control unit 36A turns off the high-side recovery switch element Q5 and turns on the ground switch element Q7 for the second power recovery unit 5X. On the other hand, for the first power recovery unit 5Y, the ground switch element Q7 is turned off. Here, since the resonance current IL is attenuated to substantially zero, no switching loss occurs.
The controller 36A further turns on the first low-side main switch element Q2 and the second high-side main switch element Q3. Here, since the voltage across the two main switch elements Q2 and Q3 is equal to zero, no switching loss occurs.
Thus, the sustaining voltage pulse Vp is clamped to a negative peak value.
When the discharge is maintained in the PDP 20, power for maintaining the discharge current is supplied from the PFC converter 40 to the PDP 20 through the input terminal 1T and the transformer 2.

Similarly, the control unit 36A changes the polarity of the sustaining voltage pulse Vp from negative to positive by on / off control for the main switch elements Q1 to Q4, the recovery switch elements Q5 and Q6, and the ground switch element Q7.
Thus, the inductor L of the power recovery units 5Y and 5X alternately resonates with the panel capacitance Cp of the PDP 20 every time the discharge sustaining pulse voltage Vp rises / falls, and power is generated between the panel capacitance Cp and the capacitor C of the power recovery unit. Are replaced efficiently. As a result, reactive power due to charging / discharging of the panel capacity is reduced.

  In the PDP driving device according to the twentieth embodiment of the present invention, the power recovery unit functions in the same manner as the power recovery unit according to the seventh embodiment as described above. Thereby, the same effects as those according to the seventeenth embodiment are provided. In particular, the resonance current does not flow through the secondary winding 2b of the transformer 2.

<< Embodiment 21 >>
In the plasma display according to the twenty-first embodiment of the present invention, similarly to the plasma display according to the eighteenth embodiment, the secondary windings 2bY and 2bX of the two transformers 2Y and 2X are connected in series with the panel capacitance Cp of the PDP 20, and two PDP driving devices are provided. Two power recovery units 5Y and 5X are included on the secondary side of the transformers 2Y and 2X (see FIG. 31). Except for the circuit configuration of the power recovery units 5Y and 5X, the configuration of both plasma displays is the same. The description of the eighteenth embodiment is incorporated for details of similar components.

Each of the power recovery units 5Y and 5X has the same circuit configuration as the power recovery units 5Y and 5X according to the twentieth embodiment (see FIGS. 36 and 37). However, the second power recovery unit 5X is connected to the sustain electrode X of the PDP 20 through the initialization pulse generator 3X (the fourth separation switch element QS6 (see FIG. 7)).
In FIG. 37, the same reference numerals as those shown in FIGS. 32 and 36 are given to the same components as those shown in FIGS. Furthermore, the description about Embodiment 18 and 20 is used for the detail of those similar components.

The secondary windings 2bY and 2bX of the two transformers 2Y and 2X are connected with their polarities reversed, for example, as shown in FIG. At that time, the controller 37 maintains the switching operations of the two sustaining pulse generators 1Y and 1X in substantially the same phase.
Apart from the example shown in FIG. 37, the secondary windings 2bY and 2bX of the two transformers 2Y and 2X may be connected with the same polarity. At that time, the controller 37 maintains the switching operations of the two sustaining pulse generators 1Y and 1X in substantially opposite phases.

  The control unit 37 further matches the switching operation of the power recovery units 5Y and 5X with the switching operation of the power recovery units 5Y and 5X according to the twentieth embodiment. As a result, the inductor L of the power recovery unit 5Y, 5X alternately resonates with the panel capacitance Cp of the PDP 20 at every rise / fall of the sustaining voltage pulse Vp, and the panel capacitance Cp and the capacitor C of the power recovery unit 5Y, 5X The power is efficiently exchanged between the two. As a result, reactive power due to charging / discharging of the panel capacity is reduced.

  In addition to the above switching control, the control unit 37 sets a predetermined phase difference (greater than 0 ° and smaller than 180 °) between the switching operations of the two sustaining pulse generating units 1Y and 1X and the two ground switch elements Q7. It may be provided (see FIG. 16). Even in this case, the inductors L of the two power recovery units 5Y and 5X alternately resonate with the panel capacitance Cp of the PDP 20 at every rising / falling of the sustaining voltage pulse Vp. Due to these resonances, power is efficiently exchanged between the panel capacitance Cp and the two capacitors C. As a result, reactive power resulting from charging / discharging of the panel capacitance Cp is reduced.

In the PDP driving device according to the twenty-first embodiment of the present invention, the power recovery unit functions in the same manner as the power recovery unit according to the eighteenth embodiment as described above. Thereby, the same effect as that according to the eighteenth embodiment is provided.
Especially when the switching operation of the two discharge sustaining pulse generators 1Y and 1X and the two power recovery units 5Y and 5X is maintained in the same phase (or opposite phase), the above resonance current is generated by the two transformers 2Y and 2X. None of the secondary windings 2bY and 2bX flow.

<< Embodiment 22 >>
In the plasma display according to the twenty-second embodiment of the present invention, similarly to the plasma display according to the nineteenth embodiment, the secondary windings 2bA and 2bB of the two transformers 2A and 2B are connected in parallel with the panel capacitance Cp of the PDP 20, and the PDP driving device 10 is Two power recovery units 5Y and 5X are included on the secondary side of the transformers 2A and 2B (see FIG. 38). Except for the circuit configurations of the power recovery units 5Y and 5X, the configurations of both plasma displays are the same (see FIG. 33).
Similarly to the control unit 38 according to the nineteenth embodiment, the control unit 38A controls switching of each of the sustaining pulse generating units 1A and 1B, the initialization / scanning pulse generating unit 3, and the address electrode driving unit (not shown) according to the ADS method. To do.
In FIG. 38, constituent elements similar to those shown in FIG. 33 are assigned the same reference numerals as those shown in FIG. Further, the description of the nineteenth embodiment is incorporated for details of similar components.

Each of the power recovery units 5Y and 5X has the same circuit configuration as the power recovery units 5Y and 5X according to the twentieth embodiment (see FIGS. 36 and 39).
39, the same reference numerals as those shown in FIGS. 34 and 36 are given to the same components as those shown in FIGS. Furthermore, the description about Embodiment 19 and 20 is used for the detail of those similar components.

The secondary windings 2bA and 2bB of the two transformers 2A and 2B are connected with the same polarity as shown in FIG. 39, for example. At that time, the controller 38A maintains the switching operations of the two sustaining pulse generators 1A and 1B in substantially the same phase.
The secondary windings 2bA and 2bB of the two transformers 2A and 2B may be connected with their polarities different from the example shown in FIG. At that time, the controller 38A maintains the switching operations of the two sustaining pulse generators 1A and 1B in substantially opposite phases.

  The control unit 38A further matches the switching operation of the power recovery units 5Y and 5X with the switching operation of the power recovery units 5Y and 5X according to the twentieth embodiment. As a result, the inductor L of the power recovery unit 5Y, 5X alternately resonates with the panel capacitance Cp of the PDP 20 at every rise / fall of the sustaining voltage pulse Vp, and the panel capacitance Cp and the capacitor C of the power recovery unit 5Y, 5X The power is efficiently exchanged between the two. As a result, reactive power due to charging / discharging of the panel capacity is reduced.

  In the PDP driving device according to the twenty-second embodiment of the present invention, the power recovery unit functions similarly to the power recovery unit according to the nineteenth embodiment as described above. Thereby, the same effect as that of the nineteenth embodiment is provided. In particular, the above resonance current does not flow through the secondary windings 2bA and 2bB of the two transformers 2A and 2B.

<< Embodiment 23 >>
In the PDP driving apparatus according to the eighteenth embodiment of the present invention, the secondary windings 2bY and 2bX of the two transformers 2Y and 2X and the panel capacitance Cp of the PDP 20 are connected in series (see FIGS. 31 and 32). In this configuration, for example, one drive unit may not include the power recovery unit as follows (see FIG. 40). Thereby, the number of parts is reduced and the mounting area is reduced.

The first drive unit 10Y includes a power recovery unit 5 on the secondary side of the first transformer 2Y. On the other hand, the second drive unit 10X does not include a power recovery unit.
The circuit configuration of the power recovery unit 5 is the same as, for example, the power recovery unit 5 according to the seventeenth embodiment (see FIG. 30).
In FIG. 40, constituent elements similar to those shown in FIG. 32 are assigned the same reference numerals as those shown in FIG. Furthermore, the description about Embodiment 18 is used for details of the similar components.

  The control unit 37 (see FIG. 31) is exactly the same (greater than 0 ° and smaller than 180 °) phase difference between the switching operations of the two sustaining pulse generation units 1Y and 1X, just like the control unit 34 according to the fifteenth embodiment. Set. As a result, as in the fifteenth embodiment, the inductor L of the power recovery unit 5 resonates with the panel capacitance Cp of the PDP 20 at every rising / falling of the sustaining voltage pulse Vp. Due to the resonance, power is efficiently exchanged between the panel capacitance Cp and the inductor L. As a result, reactive power resulting from charging / discharging of the panel capacitance Cp is reduced.

  In the PDP driving device according to the twenty-third embodiment of the present invention, the single power recovery unit 5 functions in the same manner as the two power recovery units 5Y and 5X according to the eighteenth embodiment as described above, and provides the same effect.

<< Embodiment 24 >>
In the PDP driving apparatus according to the eighteenth embodiment of the present invention, the secondary windings 2bY and 2bX of the two transformers 2Y and 2X and the panel capacitance Cp of the PDP 20 are connected in series (see FIGS. 31 and 32). Furthermore, each of the power recovery units 5Y and 5X includes two recovery switch elements Q5 and Q6 to constitute a bidirectional switch.
In this configuration, for example, as described below, the power recovery unit may include only a unidirectional switch so that only one-way current flows through the inductor L (see FIG. 41). Thereby, the number of parts is reduced and the mounting area is reduced.

The power recovery units 51Y and 51X are the same as those obtained by replacing the bidirectional switches Q5, Q6, D1, and D2 included in the power recovery units 5Y and 5X according to the eighteenth embodiment with unidirectional switches Q5 and D1, for example (see FIG. 32, 41). That is, each power recovery unit 51Y, 51X includes only one set of parallel connection of recovery switch element Q5 and diode D1. The parallel connection is connected in series with the inductor L. Thereby, the recovery switch element Q5 can cut off only the current in the reverse bias direction of the diode D1.
In FIG. 41, constituent elements similar to those shown in FIG. 32 are denoted by the same reference numerals as those shown in FIG. Furthermore, the description about Embodiment 18 is used for details of the similar components.

The control unit 37 (see FIG. 31) is exactly the same (greater than 0 ° and smaller than 180 °) phase difference between the switching operations of the two sustaining pulse generation units 1Y and 1X, just like the control unit 34 according to the sixteenth embodiment. Set. Accordingly, as in the sixteenth embodiment, the inductors L of the two power recovery units 5Y and 5X alternately resonate with the panel capacitance Cp of the PDP 20 at every rising / falling of the sustaining voltage pulse Vp. Due to the resonance, power is efficiently exchanged between the panel capacitance Cp and the inductor L. As a result, reactive power due to charging / discharging of the panel capacitance Cp is reduced.
Particularly in those resonances, the resonance current IL flows through the inductor L only in one direction.

  In the PDP driving device according to the twenty-fourth embodiment of the present invention, the two power recovery units 51Y and 51X function in the same manner as the two power recovery units 5Y and 5X according to the eighteenth embodiment as described above, and provide similar effects.

  The present invention relates to a drive device for a capacitive load such as a PDP, for example, and as described above, a transformer is provided on the output side of the pulse generator. Thereby, the DC-DC converter can be removed from the input side of the pulse generator. Thus, the present invention is clearly industrially applicable.

It is a block diagram which shows the structure of the plasma display by Embodiment 1 of this invention. FIG. 2 is an equivalent circuit diagram of a sustaining pulse generating unit 1, a transformer 2, an inductor L, and a PDP 20 according to Embodiment 1 of the present invention. FIG. 3 is an equivalent circuit diagram of the initialization / scanning pulse generator 3 according to the embodiment of the present invention, and particularly shows the connection between the initialization / scanning pulse generator 3 according to the first aspect and the secondary winding 2b of the transformer 2; Show. FIG. 3 is an equivalent circuit diagram of the initialization / scanning pulse generation unit 3 according to the embodiment of the present invention, and particularly shows the connection between the initialization / scanning pulse generation unit 3 and the secondary winding 2b of the transformer 2 according to the second mode. Show. In the first embodiment of the present invention, the potential of the scan electrode Y of the PDP 20 and the switch units Q5, Q6, Q7 included in the initialization / scan pulse generation unit 3 in the initialization period, the address period, and the discharge sustain period, FIG. 6 is a waveform diagram showing on-periods of main switch elements Q1 to Q4 included in Q8, Q9, Q10, Q11, QR1, QR2, QB, QS1, QS2, QS3, QS4, QS5, and the discharge sustaining pulse generator 1. It is a block diagram which shows the structure of the plasma display by Embodiment 2 of this invention. FIG. 5 is an equivalent circuit diagram of two driving units and a PDP 20 of the PDP driving device according to Embodiment 2 of the present invention. In the second embodiment of the present invention, each potential of the scan electrode Y and the sustain electrode X of the PDP 20 in the initialization period, the address period, and the discharge sustain period, and the main included in the discharge sustain pulse generators 1Y and 1X It is a wave form diagram which shows the ON period of switch element Q12, Q13, QS6 contained in switch element Q1Y-Q4Y, Q1X-Q4X, and the initialization pulse generation part 3X. In the second embodiment of the present invention, when a predetermined phase difference is set between the switching operations of the two discharge sustain pulse generators 1Y and 1X during the discharge sustain period, the scan electrode Y and the sustain electrode X of the PDP 20 FIG. 6 is a waveform diagram showing each potential and the ON period of main switch elements Q1Y to Q4Y and Q1X to Q4X included in discharge sustain pulse generators 1Y and 1X. It is a block diagram which shows the structure of the plasma display by Embodiment 3 of this invention. FIG. 5 is an equivalent circuit diagram of two driving units and a PDP 20 of a PDP driving device according to Embodiment 3 of the present invention. It is a block diagram which shows the structure of the plasma display by Embodiment 4 of this invention. It is the equivalent circuit schematic of the PDP drive device by Embodiment 4 of this invention, and PDP20. It is a block diagram which shows the structure of the plasma display by Embodiment 5 of this invention. FIG. 6 is an equivalent circuit diagram of two driving units and a PDP 20 of a PDP driving device according to Embodiment 5 of the present invention. In the fifth embodiment of the present invention, when a predetermined phase difference is set between the switching operations of the two discharge sustain pulse generators 1Y and 1X during the discharge sustain period, the two discharge sustain pulse generators 1Y and 1X ON period of the recovery switch elements Q5 and Q6 included in the main switch elements Q1 to Q4 included and the power recovery units 4Y and 4X, the discharge sustaining pulse voltage Vp, and the resonance current IL flowing through the inductor L of the power recovery units 4Y and 4X FIG. It is a block diagram which shows the structure of the plasma display by Embodiment 6 of this invention. FIG. 9 is an equivalent circuit diagram of two driving units and a PDP 20 of a PDP driving device according to Embodiment 6 of the present invention. FIG. 9 is an equivalent circuit diagram of a PDP driving device and a PDP 20 according to Embodiment 7 of the present invention. FIG. 10 is an equivalent circuit diagram of two driving units and a PDP 20 of a PDP driving device according to an eighth embodiment of the present invention. FIG. 10 is an equivalent circuit diagram of a PDP driving device and a PDP 20 according to Embodiment 9 of the present invention. FIG. 12 is an equivalent circuit diagram of two driving units and a PDP 20 of the PDP driving device according to the tenth embodiment of the present invention. It is the equivalent circuit schematic of the PDP drive device by Embodiment 11 of this invention, and PDP20. FIG. 14 is an equivalent circuit diagram of two driving units and a PDP 20 of a PDP driving device according to a twelfth embodiment of the present invention. It is the equivalent circuit schematic of the PDP drive device by Embodiment 13 of this invention, and PDP20. FIG. 16 is an equivalent circuit diagram of two driving units and a PDP 20 of the PDP driving device according to Embodiment 14 of the present invention. FIG. 17 is an equivalent circuit diagram of two driving units and a PDP 20 of the PDP driving device according to the fifteenth embodiment of the present invention. FIG. 18 is an equivalent circuit diagram of two driving units and a PDP 20 of a PDP driving device according to a sixteenth embodiment of the present invention. It is a block diagram which shows the structure of the plasma display by Embodiment 17 of this invention. FIG. 18 is an equivalent circuit diagram of a PDP driving device according to a seventeenth embodiment of the present invention and a PDP 20. It is a block diagram which shows the structure of the plasma display by Embodiment 18 of this invention. FIG. 20 is an equivalent circuit diagram of two driving units of a PDP driving device according to an eighteenth embodiment of the present invention and a PDP 20. It is a block diagram which shows the structure of the plasma display by Embodiment 19 of this invention. FIG. 20 is an equivalent circuit diagram of two driving units and a PDP 20 of the PDP driving device according to the nineteenth embodiment of the present invention. It is a block diagram which shows the structure of the plasma display by Embodiment 20 of this invention. FIG. 20 is an equivalent circuit diagram of the PDP driving device according to Embodiment 20 of the present invention and PDP 20. FIG. 22 is an equivalent circuit diagram of two driving units of a PDP driving device according to a twenty-first embodiment of the present invention and a PDP 20. It is a block diagram which shows the structure of the plasma display by Embodiment 22 of this invention. It is an equivalent circuit diagram with two drive parts of the PDP drive device by Embodiment 22 of this invention, and PDP20. It is an equivalent circuit diagram with two drive parts of PDP drive device by Embodiment 23 of this invention, and PDP20. FIG. 25 is an equivalent circuit diagram of two driving units and a PDP 20 of the PDP driving device according to the twenty-fourth embodiment of the present invention. It is a block diagram which shows the structure of the conventional plasma display. FIG. 3 is an equivalent circuit diagram of a conventional sustaining pulse generating unit 102 including a push-pull inverter and a PDP 20. FIG. 5 is an equivalent circuit diagram of a conventional sustaining pulse generation unit 102 including a full bridge inverter unit 102a and two similar power recovery units 102b and 102c, and a PDP 20; FIG. 5 is an equivalent circuit diagram of a conventional sustaining pulse generation unit 102 including a full-bridge inverter unit 102a and another power recovery unit 102d, and a PDP 20.

Explanation of symbols

10 PDP drive
1T input terminal
2 transformer
2a Primary winding of transformer 2
2b Secondary winding of transformer 2
L inductor
20 PDP
X1, X2, X3 PDP20 sustain electrodes
Y1, Y2, Y3 PDP20 scan electrode
AC External AC power supply
Output voltage of Vs PFC converter 40
VF Primary pulse voltage
Vp Discharge sustain pulse voltage

Claims (31)

A device for applying a predetermined pulse voltage to a capacitive load;
A pulse generation unit including a switch element, which converts a predetermined DC voltage into a primary pulse voltage by switching of the switch element; and
A primary winding connected to the pulse generation unit; and a secondary winding connected to the capacitive load, the primary pulse voltage is converted into the pulse voltage, and an excitation inductance is converted into the capacitive load. Transformer to resonate with;
Capacitive load driving device.   The capacitive load driving device according to claim 1, wherein an excitation inductance of the transformer resonates with the capacitive load during a rising period and a falling period of the pulse voltage or the primary pulse voltage. A first drive unit and a second drive unit each having the pulse generation unit and the transformer;
The capacitive load driving device according to claim 1, comprising: A control unit for maintaining the switching operation of the first driving unit and the switching operation of the second driving unit in the same phase or in opposite phase;
The capacitive load driving device according to claim 3, comprising: When the secondary winding of the transformer and the capacitive load are connected in series,
A control unit for setting a phase difference between the switching operation of the first driving unit and the switching operation of the second driving unit in a range larger than 0 ° and smaller than 180 °;
The capacitive load driving device according to claim 3, comprising: A device for applying a predetermined pulse voltage to a capacitive load;
A pulse generator including a switch element and converting a predetermined DC voltage into a primary pulse voltage by switching of the switch element;
A transformer that includes a primary winding connected to the pulse generator, and a secondary winding connected to the capacitive load, and converts the primary pulse voltage to the pulse voltage;
An auxiliary inductor connected in parallel with the secondary winding of the transformer and resonating with the capacitive load;
Capacitive load driving device.   The capacitive load driving device according to claim 6, wherein the auxiliary inductor resonates with the capacitive load during a rising period and a falling period of the pulse voltage or the primary pulse voltage.   The capacitive load driving device according to claim 6, wherein an inductance of the auxiliary inductor is smaller than an excitation inductance of the transformer. A first driver having the pulse generator, the transformer, and the auxiliary inductor; and
A second drive unit having the pulse generation unit and the transformer;
The capacitive load driving device according to claim 6, comprising:   The capacitive load driving device according to claim 9, wherein the second driving unit includes the auxiliary inductor. A control unit for maintaining the switching operation of the first driving unit and the switching operation of the second driving unit in the same phase or in opposite phase;
The capacitive load driving device according to claim 9, comprising: When the secondary winding of the transformer and the capacitive load are connected in series,
A control unit for setting a phase difference between the switching operation of the first driving unit and the switching operation of the second driving unit in a range larger than 0 ° and smaller than 180 °;
The capacitive load driving device according to claim 9, comprising:   The capacitive load driving device according to claim 1, wherein the pulse generation unit regenerates electric power to the DC voltage supply source by switching of the switching element.   The capacitive load driving device according to claim 1, wherein the switch element of the pulse generation unit is a wide bandgap semiconductor switch element. The pulse generation unit includes a high-side switch element and a low-side switch element as the switch elements, and the high-side switch element and the low-side switch element are connected in series;
A primary winding of the transformer is connected to a connection point between the high-side switch element and the low-side switch element;
The capacitive load driving device according to claim 1 or 6.   The capacitive load driving device according to claim 15, wherein at the end of application of the pulse voltage, one of the high-side switch element and the low-side switch element is turned on to pass a regenerative current to the DC voltage supply source. A device for applying a predetermined pulse voltage to a capacitive load;
A pulse generator including a switch element and converting a predetermined DC voltage into a primary pulse voltage by switching of the switch element;
A power recovery unit comprising: an inductor; and a switch unit for passing a current associated with resonance between the inductor and the capacitive load during an ON period; and
A transformer that includes a primary winding connected to the pulse generator and a secondary winding connected to the capacitive load, and converts the primary pulse voltage into the pulse voltage;
A capacitive load driving device comprising:   The capacitive load driving device according to claim 17, wherein the power recovery unit is connected to the primary winding of the transformer.   The capacitive load driving device according to claim 17, wherein the power recovery unit is connected to the secondary winding of the transformer.   The capacitive load driving device according to claim 17, wherein the switch unit makes the ON period coincide with a rising period and a falling period of the pulse voltage or the primary pulse voltage.   The capacitive load driving device according to claim 17, wherein the inductor and the switch unit are connected in series in the power recovery unit. A first drive unit having the pulse generator, the power recovery unit, and the transformer; and
A second drive unit having the pulse generation unit and the transformer;
The capacitive load driving device according to claim 17, comprising:   The capacitive load driving device according to claim 22, wherein the second driving unit includes the power recovery unit.   The capacitive load driving device according to claim 22, further comprising a control unit that maintains a switching operation of the first driving unit and a switching operation of the second driving unit in the same phase or in opposite phase. When the secondary winding of the transformer and the capacitive load are connected in series,
A control unit for setting a phase difference greater than 0 ° and smaller than 180 ° between the switching operation of the first drive unit and the switching operation of the second drive unit;
The capacitive load driving device according to claim 22, comprising:   26. The capacitive load driving device according to claim 25, wherein the switch unit of the power recovery unit allows a current accompanying the resonance to flow in one direction.   The capacitive load driving device according to claim 17, wherein the switch element of the pulse generation unit is a wide bandgap semiconductor switch element. The pulse generation unit includes a high-side switch element and a low-side switch element as the switch elements, and the high-side switch element and the low-side switch element are connected in series;
A primary winding of the transformer is connected to a connection point between the high-side switch element and the low-side switch element;
The capacitive load driving device according to claim 17. A rectifying unit for converting an AC voltage from an external power source into a predetermined DC voltage;
A plasma display panel (PDP) driving device for converting the DC voltage into a predetermined pulse voltage; and
A PDP comprising: a discharge cell that emits light by discharge of a gas enclosed therein; and a plurality of electrodes that apply the pulse voltage to the discharge cell;
A plasma display having
The PDP driving device is
A pulse generator including a switch element, and converts the DC voltage into a primary pulse voltage by switching of the switch element; and
A primary winding connected to the pulse generator, and a secondary winding connected to the electrode of the PDP, the primary pulse voltage is converted into the pulse voltage, and an excitation inductance is provided between the electrodes. Transformer to resonate with the capacitance of
A plasma display. A rectifying unit for converting an AC voltage from an external power source into a predetermined DC voltage;
A PDP driving device for converting the DC voltage into a predetermined pulse voltage; and
A PDP comprising: a discharge cell that emits light by discharge of a gas enclosed therein; and a plurality of electrodes that apply the pulse voltage to the discharge cell;
A plasma display having
The PDP driving device is
A pulse generation unit including a switch element and converting the DC voltage into a primary pulse voltage by switching of the switch element;
A transformer that includes a primary winding connected to the pulse generator and a secondary winding connected to the electrode of the PDP, and converts the primary pulse voltage to the pulse voltage; and
An auxiliary inductor connected in parallel with the secondary winding of the transformer and resonating with the capacitance between the electrodes;
A plasma display. A rectifying unit for converting an AC voltage from an external power source into a predetermined DC voltage;
A PDP driving device for converting the DC voltage into a predetermined pulse voltage; and
A PDP comprising: a discharge cell that emits light by discharge of a gas enclosed therein; and a plurality of electrodes that apply the pulse voltage to the discharge cell;
A plasma display having
The PDP driving device is
A pulse generation unit including a switch element and converting the DC voltage into a primary pulse voltage by switching of the switch element;
A power recovery unit comprising: an inductor; and a switch unit for passing a current associated with resonance between the inductor and the capacitance between the electrodes of the PDP in an ON period; and
A transformer that includes a primary winding connected to the pulse generator and a secondary winding connected to the electrode of the PDP, and converts the primary pulse voltage to the pulse voltage;
A plasma display.

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