JPH1152908A - Driving device for plasma display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent occurrence of a noise to stabilize a system, and to reduce power consumption at the time of driving a switch by utilizing electrode capacity of a plasma display panel and a resonance characteristic of a coil provided in a driving device. SOLUTION: A switch SW7 is turned on and a row electrode is kept at a ground potential in a scanning period. Next, switches SW8 and SW9 are turned on, the switch SW7 is turned off, a switch SW2 is turned on, electric charges of a capacitor C1 for withdrawing electric charges are supplied to an output 01 through a coil L1, a diode D1, and the switch SW8, and electric charges are charged to row electrodes. At the time, a rising part and a falling part of a scanning pulse are made a waveform having loose tilt owing to resonance by the coil L1 and electrode capacity of PDP. Thus, a waveform in which high frequency components are reduced is made at the time of rising and falling of a scanning pulse, needless radiation of an electromagnetic wave is reduced, and increasing power consumption by a high frequency wave is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving apparatus for a PDP (Plasma Display Panel), and more particularly to a technique for improving a waveform during a scanning pulse.

[0002]

2. Description of the Related Art As is well known, various studies have recently been made on a PDP as one of thin two-dimensional screen displays.
One of them is an AC discharge type matrix PDP having a memory function. Such a PDP includes a column electrode and a pair of row electrodes orthogonal to the column electrode and constituting one row (one scanning line). Each of the column electrode and the row electrode pair is a dielectric layer with respect to the discharge space. And a discharge cell (pixel) is formed at each intersection of the column electrode and the row electrode pair. The PDP drive sequence includes a reset period for generating a reset pulse for forming or erasing wall charges by forcibly discharging and exciting all the row electrode pairs, and a scan period for generating a scan pulse for writing pixel data. A period and a sustain period for generating a sustain pulse for maintaining discharge light emission.

FIG. 1 shows a driving device for driving a row electrode pair of a PDP. In FIG. 1, reference numeral 1 denotes a first pulse generation circuit for generating a sustain pulse, and 2 denotes a second pulse generation circuit for generating a reset pulse. The circuit 3 is a third pulse generating circuit that generates a scanning pulse. One first and second pulse generation circuits 1 and 2 are provided for all row electrodes or a plurality of row electrode groups, and a third pulse generation circuit 3 is provided for all row electrodes or a plurality of row electrode groups. One is provided to generate a scanning pulse for each of the name row electrodes,
Pulses from the first pulse generation circuit 1 and the second pulse generation circuit are supplied to each row electrode via the third pulse generation circuit 3. The first pulse generation circuit 1 includes a series circuit of a constant voltage source E1 and a switch SW1, a coil L1, and a switch SW1.
2, a series circuit of a diode D1, a coil L2, a switch SW3, a series circuit of a diode D2, and a switch SW4.
And a charge collection capacitor C1. The series circuit including the coils L1 and L2 has a charge recovery capacitor C
1 is connected, and the switch SW4 is connected to the ground. Each series circuit and the switch SW4 are connected in parallel with each other.

[0004] The second pulse generating circuit comprises a series circuit of a constant voltage source E2, a switch SW5 and a resistor R1. The third pulse generating circuit 3 includes a constant voltage source E3, switches SW6 to SW9, and diodes D3 and D4, and an output O1 is connected to each row electrode. To the constant voltage source E3, a series circuit including a plurality of switches SW6 and SW7 provided corresponding to the row electrodes of the PDP is connected in parallel. Diodes D3 and D4 are also connected in series corresponding to the row electrodes of the PDP, and a plurality of diodes D3 and D4 are provided corresponding to the row electrodes. The common connection point is connected to the common connection point of switches SW6 and SW7. Also, a switch SW8,
SW9 and diodes D3 and D4 are means for controlling the supply of pulse outputs from the first and second pulse generation circuits 1 and 2 to each row electrode.

The operation of the above configuration will be described with reference to the timing chart of FIG. During the reset period from time t1 to t3 and the sustain period from time t9 to t13, the switches SW8 and SW9 are turned on and the switch SW8 is turned on.
6, SW7 is off, and switches SW8 and SW9 are off during the scanning period from time t3 to t9. In the reset period, before time t1, the switch SW4 is on, and the row electrode is at the ground potential. At time t11, the switch SW4 turns off and the switch S
When W5 is turned on, a reset pulse is simultaneously supplied to each row electrode from the constant voltage source E2 through the switch SW8 and the diode D3. This reset pulse has a waveform that rises according to the time constant of the resistance R1 and the electrode capacitance of the PDP. At time t2, the switch SW
4 is turned on, the switch SW5 is turned off, and the row electrode returns to the ground potential again.

Next, in the scanning period, the switches SW8 and SW9 are turned off at time t3 and the switch SW7 is turned on, so that the row electrode maintains the ground potential. Then, at time t4, the switch SW6 is turned on. When SW7 is turned off, the constant voltage source E3 is supplied to the row electrode. At time t6, the switch SW6 is turned off, and when the switch SW7 is turned on, the row electrode is set to the ground potential. Next, at time t7, the switch SW6 is turned on again and the switch SW7 is turned off, so that the constant voltage source E3 is supplied to the row electrode. At time t9, the switch SW6 is turned off and the switch SW7 is turned on. As described above, during the scanning period, the switches SW6 and SW7 operate complementarily, and at the time t4 to t6
The pulse generated during the period is a priming pulse for forming wall charges, and the pulse generated during the period from time t6 to time t7 is supplied to the row electrodes as a scanning pulse. Here, the priming pulse (time t4 to t6 period) and the scanning pulse (time t6 to t7 period) are sequentially shifted for each row electrode. Corresponding pixel data pulses are sequentially applied to the column electrodes (not shown).

Next, when the scanning period ends, the operation moves to the sustain period. In this maintenance period, first, at time t9, the switch SW
6, SW7 is turned off, and switches SW8, SW9 are turned on. At this time, since the switch SW4 is on, the row electrode is at the ground potential. Next, at time t10, the switch SW4 is turned off and the switch SW2 is turned on, so that the charge of the charge collection capacitor C1 is transferred to the coil L.
1, diode D1, switch SW8, diode D3
To the row electrode of the PDP connected to the output O1 through the gate, and charges the row electrode group. At this time, the coil L1
And a pulse having a gradual rise is obtained by resonance due to the electrode capacitance of the PDP. After charging the electrode capacity, time t
When the switch SW2 is turned off and the switch SW1 is turned on at 11, the constant voltage source E1 is supplied to the row electrode.
Next, at time t12, the switch SW1 is turned off and the switch S
When W3 is turned on, the constant voltage source E1 is disconnected, and the positive voltage of the output O1 is changed to the diodes D4 and D2 and the coil L
2. Charge recovery capacitor C1 through switch SW3
To discharge the accumulated charge of the PDP. And
At time t13, the switch SW3 turns off and the switch SW
When 4 is turned on, the residual charge of the electrode capacitance of the PDP is discharged, and the row electrode becomes the ground potential. This period t12−
Also at t13, a gentle falling pulse is obtained by resonance due to the coil L2 and the electrode capacitance of the PDP.
By repeating the above operation, a predetermined number of sustain pulses are generated.

[0008]

In such a driving apparatus, the edge of the waveform becomes sharp at the rise and fall of the scanning pulse, and high frequency noise and the like are easily generated in the periphery. This high-frequency noise causes electromagnetic interference and the like, and the operation of the driving device becomes unstable.

The present invention has been made in view of the above circumstances, and uses the electrode capacitance of a PDP and the resonance characteristics of a coil provided in a driving device to prevent the occurrence of high-frequency noise, stabilize the system, and perform switching drive. It is an object of the present invention to provide a PDP driving device capable of reducing power consumption at the time.

[0010]

According to a first aspect of the present invention, there is provided a driving apparatus for a plasma display panel for supplying a scanning pulse to a plurality of row electrodes of a plasma display panel in a time-series manner. And driving means for driving at the time of rising and / or falling of the scanning pulse. The driving means includes a coil, and the scanning pulse rises and / or falls by resonance caused by the coil and the capacitance of the plasma display panel. I do.

The invention described in claim 2 is the first invention.
5. The driving device for a plasma display panel according to item 1, wherein the driving unit also serves as a unit for driving at the time of rising and / or falling of the sustain pulse included in the sustain pulse generating unit for generating the sustain pulse. It is characterized by.

[0012]

According to the present invention, it is possible to prevent the occurrence of high-frequency noise, stabilize the system, and reduce the power consumption at the time of driving the switch by utilizing the electrode capacitance of the PDP and the resonance characteristics of the coil provided in the driving device. it can.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a driving device according to one embodiment is the same as that in FIG. Hereinafter, the operation will be described with reference to FIG. The reset period from time t1 to t3 is the same as the operation described with reference to FIG. 3, and discharge is generated between all the row electrode pairs by applying the reset pulse.
Charged particles are generated in each pixel cell, and wall charges are accumulated and formed after the discharge ends. The reset pulse has a slowly rising waveform. Thereby, while the potential change appearing on the row electrode has a gentle rising waveform and the discharge current flowing through the cell is small,
Only a small amount of current flows gently in the cell, thereby suppressing the amount of discharge energy in the pixel cell. Therefore, the brightness of the discharge light emission due to the application of the reset pulse is reduced and lowered, and the contrast in the PDP can be improved.

In the scanning period, the switch SW7 is turned on during the period from time t3 to t4 as in FIG. 3, and the row electrode is maintained at the ground potential. Next, at time t4, the switches SW8 and SW9 are turned on, the switch SW7 is turned off, and the switch SW2 is turned on. Thereby, the electric charge of the electric charge recovery capacitor C1 is supplied to the output O1 through the coil L1, the diode D1, and the switch SW8 to the row electrode, and the electric charge is charged between the row electrodes. At this time, the coil L1
A pulse having a gentle rise is obtained by resonance due to the electrode capacitance of the PDP, and the rising and falling portions of the scan pulse have a gentle slope waveform due to the resonance characteristics of the LC.

That is, at time t4, conventionally, the switch SW6 is turned on and the switch SW7 is turned off to make the priming pulse rise steeply. However, in the present invention, the switches SW6 and SW7 are turned off and the switch is turned off. S
By turning on W8 and SW9, and further turning on the switch SW2, it starts up by LC resonance.

Next, when the priming pulse rises to a predetermined voltage, the switches SW8 and SW9 are turned off and the switch SW6 is turned on at time t5 to supply a positive voltage from the constant voltage source E3 as in the operation of FIG. . Time t
6, the switch SW6 is turned off and the switch SW7 is turned on to set the row voltage to the ground potential. At time t7, the switch SW6 is turned off.
6 is turned on, SW7 is turned off, and a positive voltage is generated again to generate a scanning pulse.

Next, at time t8, the switch SW
8, the switch SW9 is turned on, the switch SW6 is turned off (the switch SW7 is turned off at this time), and the switch SW3 is turned on. As a result, the constant voltage source E3 is disconnected, and the positive voltage of the output O1 is changed to the diode D4, the switch SW9, the diode D2, the coil L2, and the switch SW3.
Through the charge recovery capacitor C1 through the PDP
Is discharged. That is, a falling waveform is obtained by resonance due to the capacitance of the coil L2 and the electrode capacitance of the PDP as in the case of the generation of the sustain pulse. Then, at time t9, the switch SW3 is turned off and the switch SW4 is turned on, so that the row electrode becomes the ground potential. As described above, even when the scanning pulse rises and falls, the waveform has a reduced harmonic component, so that unnecessary radiation of electromagnetic waves is reduced and an increase in power consumption due to the harmonics can be suppressed.

In the timing chart of FIG. 2, during the scanning period, pixel data pulses corresponding to the pixel data of each row are sequentially applied to the column electrodes (not shown), and are synchronized with the application timing of each pixel data pulse. The scanning pulse is applied to the row electrodes. At this time, discharge occurs only in the pixel cells to which the pixel data pulse and the scan pulse are simultaneously applied to the column electrode and the row electrode, respectively, and most of the wall charges formed in the reset period disappear. On the other hand, no discharge occurs in the pixel cells to which the scan pulse is applied but the pixel data pulse is not applied, so that the wall charges remain. That is, the wall charges formed during the reset period are:
It is selectively erased according to the contents of the pixel data.

Next, when the operation proceeds to the maintenance period after time t9,
In the sustain discharge period, a predetermined number of sustain pulses are generated by the same operation as that described with reference to FIG. That is, only the pixel cells in which the wall charges remain during the period in which the sustain pulse is continuously applied maintain the discharge light emission. The driving operation of each switch is controlled by a controller (not shown).

In the above-described embodiment, the rising edge of the scanning pulse generated during the period from the time t6 to the time t7 during the scanning period is the same as the switching operation during the period from the time t4 to the time t5 or the time t8 to the time t9. The waveform may have a gentle fall. Alternatively, a gentle waveform may be obtained by a switch operation including the switches SW2 and SW3 only at the time of rising or falling of the pulse generated during the scanning period.

In this embodiment, the circuit including the coils L1 and L2 of the first pulse generation circuit 1 for generating the sustain pulse is also used as the waveform generation circuit at the time of the rising and falling of the scanning pulse. Alternatively, an independent drive circuit different from the first pulse generation circuit may be provided. Further, the switch SW4 is also used as a switch for setting the ground potential in each operation period, but may be provided for each period.

[0022]

As described above, according to the present invention, it is possible to prevent the occurrence of high-frequency noise, stabilize the system, and reduce the power consumption when driving the switch.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a driving circuit of a PDP according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a driving waveform of a PDP according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a driving waveform of a PDP according to an embodiment of the present invention.

[Explanation of symbols]

 1 first pulse generation circuit 2 second pulse generation circuit 3 third pulse generation circuit E1 to E3 constant voltage sources D1 to D4 ··· Diodes L1 and L2 ··· Coil C1 ··· Charge recovery capacitors SW1 and SW9 ··· Switch O1 ···· Output

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[Procedure amendment]

[Submission date] February 2, 1998

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

FIG. 3

Claims (2)

[Claims] 1. A driving apparatus for a plasma display panel for supplying a scanning pulse to a plurality of row electrodes of a plasma display panel in a time series manner, wherein a driving means for driving at the time of rising and / or falling of the scanning pulse is provided. A driving apparatus for driving a plasma display panel, wherein the driving unit includes a coil, and the scanning pulse rises and / or falls by resonance caused by the coil and the capacitance of the plasma display panel. 2. The driving device according to claim 1, wherein the driving unit also serves as a driving unit included in the sustain pulse generating unit for generating the sustain pulse and driving when the sustain pulse rises and / or falls. 3. The driving device for a plasma display panel according to claim 1.