JPH10149134A - Driving device for plasma display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power loss by providing a recovery side coil and a charging side coil in the recovery route and charging route of a bidirectional switch and making the inductance value of the recovery side coil smaller than that of the charging side. SOLUTION: In a reactive power recovery circuit 1, a high voltage side power supply 5 and the output 2 of the reactive power recovery circuit 1 are connected through a main power supply high side switch 6 and a part between the main power supply high side switch 6 and the output 2 of the reactive power recovery circuit 1 is branched and connected through the bidirectional switch composed of diodes 11 and 13 to a capacitor 10. The other end of the capacitor 10 is connected to a low voltage side power supply terminal 7, and for the bidirectional switch, the recovery side coil 91 is arranged in the recovery route and the charging side coil 92 is arranged in the charging route in addition to the diodes and the switch. The inductance of the recovery side coil 91 is turned to a value smaller than the inductance of the charging side coil. Since a current is made to flow fast, the current made to flow through a parasitic transistor to a low voltage side power supply is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display driving method for recovering and reusing reactive power generated at the time of addressing.

[0002]

2. Description of the Related Art FIG.
FIG. 1 is a circuit diagram showing a conventional plasma display driving device disclosed in Japanese Unexamined Patent Application Publication No. H10-115,004. Driver IC 3 in which output 2 of reactive power recovery circuit 1 is constituted by complementary MOS transistors
Are connected to the high-voltage side power supply terminal 4 of the power supply. The power recovery circuit 1 includes a main power supply high side switch 6 connected to a high voltage side power supply 5 for controlling a high voltage potential and a low voltage potential, a low side switch 8 connected to a low voltage side power supply terminal 7, and a high side switch. The coil 9 is composed of a coil 9 connected by branching between the low-side switch 6 and the low-side switch 8, a bidirectional switch connected to the other end of the coil 9, and a capacitor 10 connected to the other end of the bidirectional switch. The capacitor 10 is connected to the low-voltage power supply 7, the bidirectional switch controls a recovery path and a charging path, and the recovery path includes a diode 11 and a recovery switch 12, and a charging path includes a diode 13 and a charging switch 14. . The driver IC 3 is a driver IC having 32 to 64 outputs and a withstand voltage of about 200 V. Each output terminal B1 to Bn of the driver IC 3 has address electrodes A1 to An.
n. A capacitance exists between the address electrodes A1 to An and between the addresses A1 to An and the scan electrodes S1 to Sm.
1 to AHn, charge and collection of the electric charge to the capacitance are performed by the reactive power recovery circuit 1.

A driver IC 3 manufactured by a self-separation type process, which is relatively inexpensive, is often used. As shown in FIG. 10, a driver IC 3 manufactured by a self-isolation type process generally includes parasitic transistors K1 to Kn having a base connected to a high voltage side, a collector connected to a low voltage side, and an emitter connected to an output terminal. Will occur. The parasitic transistors K1 to Kn are turned on when the electric charge charged in the capacitance of the plasma display panel is collected by the reactive power recovery circuit 1 via the high-voltage side switch, and are half of the charge to be collected. The degree flows to the low voltage side through the parasitic transistors K1 to Kn. All of the charges that could not be collected are lost, increasing power consumption. This phenomenon does not occur when charging the capacitance of the panel.

[0004]

In the conventional plasma display driving apparatus as described above, since the parasitic transistors K1 to Kn are present in the driver IC 3, the electric charge charged to the capacitance of the plasma display panel is obtained. Is recovered in the reactive power recovery circuit 1, about half of the charge flows to the low voltage side via the parasitic transistors K <b> 1 to Kn, and that amount is lost and power is wasted.

Further, at the time of recovery, the potential of the high voltage side power supply terminal 4 of the driver IC 3 decreases, the operation of the driver IC high side switches AH1 to AHn becomes unstable, and the potential of the high voltage side power supply terminal 4 recovers to about 15V. Until the high-side switches AH1 to AHn and the low-side switches AL1 to ALn
Were turned on at the same time, resulting in power loss due to arm short-circuit.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem. Even if a parasitic transistor exists in a driver IC, a charge stored in a plasma display panel is recovered by a reactive power recovery circuit. In this case, the amount of electric charge flowing to the low voltage side via the parasitic transistor is reduced, and the power that is wasted is reduced.

[0007]

In a driving apparatus for a plasma display according to the present invention, a first coil and a second coil are provided in each of a recovery path and a charging path of a bidirectional switch of a reactive power recovery circuit. The inductance of the first coil is smaller than that of the second coil.

Further, a coil is arranged only in the charging path of the bidirectional switch, and a third coil is provided between the first switch and the branch of the high-voltage side power supply terminal and the bidirectional switch.

Further, the coil is arranged only in the charging path of the bidirectional switch.

Further, the low voltage power supply lines of the odd and even columns of the address electrode group are separated, a switch is provided between the power supply lines, and a second switch is provided between the bidirectional switch of the reactive power recovery circuit and the odd column low voltage power supply line. One capacitor, a second capacitor connected between a bidirectional switch and an even-column low-voltage power supply line, and all charges charged in the capacitance between the odd-column and even-column address electrodes are collected by a reactive power recovery circuit. It is.

Furthermore, the first half of the third step, which is a charging period, or the second step and the third step, which are a collection period.
In the first half of the step, a period is provided in which both the high voltage side switch and the low voltage side switch of the address circuit group are turned off.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the plasma display driving device according to the present invention, since the inductance of the first coil in the recovery path is smaller than the inductance of the second coil in the charging path, the plasma display panel is charged. When recovering the electric charge, since the impedance is lower than at the time of charging, more current can flow to the reactive power recovery circuit, and as a result, the amount of current flowing to the low voltage side through the parasitic transistor can be reduced. Can be reduced.

In addition, the third coil is not disposed on the common path through which current flows during charging and recovery, the second coil is disposed on the charging path of the bidirectional switch, and the coil is not disposed on the recovery path, so that the inductance during recovery is charged. Since the current is smaller than the inductance at the time, the current flowing to the low voltage side via the parasitic transistor can be similarly reduced.

Further, by arranging the coil only in the charging path of the bidirectional switch, since the inductance at the time of recovery is zero, the current flowing to the low voltage side via the parasitic transistor can be similarly reduced.

Further, since the low-voltage power supply lines of the odd-numbered columns and the even-numbered columns of the address electrode group are separated and a switch is provided between the power supply lines, when collecting the charged electric charge, the odd-numbered columns and the even-numbered columns are recovered. By electrically disconnecting the low-voltage power supply line by the switch, all the electric charges charged in the capacitance between the odd-numbered column and the even-numbered column address electrodes can be collected in the reactive power recovery circuit.

Further, since a period in which both the high voltage side switch and the low voltage side switch are turned off is provided over the first half of the charging period or the recovery period and the first half of the charging period, the high voltage side power supply terminal lowered at the time of recovery is provided. Since the switches of the address circuit group do not turn on until the potential recovers, the gate of the high-voltage switch becomes unstable, which is caused by the high-voltage switch and the low-voltage switch connected to the same electrode. The phenomenon of turning on at the same time can be prevented, and power loss can be reduced.

Hereinafter, the present invention will be described in detail with reference to the drawings showing the embodiments. Embodiment 1 FIG. FIG. 1 is a circuit diagram showing a driving device for a plasma display according to a first embodiment of the present invention. In the figure, 1-7, 10-14, AH1-AH
n, AL1 to ALn, B1 to Bn, A1 to An, S1 to
Sm is the same as that of the above-described conventional device, and includes a reactive power recovery circuit 1, an output 2 of the reactive power recovery circuit, and a driver I, respectively.
C3, a high-voltage side power supply terminal 4 of the driver IC 3, a high-voltage side power supply 5, a main power supply high-side switch 6 for controlling a high voltage potential, a low-voltage side power supply terminal 7, a capacitor 10, a diode 11 constituting a bidirectional switch, 13. Collection switch 1
2. Charge switch 14, high side switches AH1 to AHn of driver IC, low side switches AL1 to ALn, output terminals B1 to Bn, address electrodes A1 to An, scan electrode S
1 to Sm. The configuration of the power recovery circuit 1 will be described. The high-voltage power supply 5 and the output 2 of the reactive power recovery circuit are connected via the main power supply high-side switch 6, and the main power supply high-side switch 6 and the output 2 of the reactive power recovery circuit are branched. It is connected to the capacitor 10 via. The other end of the capacitor 10 is connected to the low-voltage side power supply terminal 7,
In the bidirectional switch, in addition to the diode and the switch, a collecting coil 91 is arranged in a collecting path, and a charging coil 92 is arranged in a charging path. The inductance of the recovery side coil is smaller than the inductance of the charging side coil.

The plasma display has an address electrode A
1 to An, the address electrodes A1 to An and the scan electrode S1.
To Sm. In order to generate a voltage between the address electrode and the scan electrode to cause discharge light emission, it is necessary to charge and discharge the capacitance of those capacitances. However, if the charge is not recovered, all the current flowing by charging and discharging the capacitance is lost, and the power occupies most of the total power consumption. The collection and charging of those capacitances are performed by the reactive power recovery circuit 1 through the driver IC high side switches AH1 to AHn in the driver IC3. The switches AH1 to AHn, AL1 to ALn of the driver IC 3 at that time
A main power supply high side switch 6, a recovery switch 12,
FIG. 2 shows a timing chart of the charging switch 14.
In the figure, the high timing indicates that the switch is on. This is a cycle in which a voltage for selecting each scanning electrode is generated at the address electrode, and the main power supply high-side switch 6 is turned off over a period in which the voltage level is switched, and the current path is switched to the reactive power recovery circuit 1 side. . Subsequently, the collection switch 12 is turned on before the voltage level of the address electrode is switched, and the high-side switch A of the driver IC 3 is turned on.
The recovery current flows through the recovery-side coil 91 through the parasitic diodes H1 to AHn to charge the capacitor 10. Next, the collection switch 12 is turned off, and after the voltage level of the address electrode is switched, the charge switch 14 is turned on. Charge capacity. And
The charging switch 14 is turned off, and the main power supply high side switch is turned on to generate a predetermined voltage between the address electrode and the scanning electrode.

When the capacitance between the electrodes is charged, the power loss is small, but when the power is recovered, the parasitic transistors K1 to Kn operate as described above, and the capacitor 1
About half of the charge to be recovered to 0 flows to the low-voltage side power supply, and the loss increases. By making the inductance value of the recovery-side coil 91 smaller than that of the charging-side coil 92, the peak value of the recovery current rises and the switching loss increases, but the current flows faster by that amount and flows to the reactive power recovery circuit 1 side. The current increases, and the current flowing to the low-voltage side power supply through the parasitic transistors K1 to Kn decreases. FIG. 3 shows the effect obtained by the experiment.
It can be seen that the power can be reduced by reducing the inductance value of the recovery side coil 91. Therefore, power consumption can be reduced as compared with a conventional plasma display driving device.

Embodiment 2 FIG. 4 is a circuit configuration diagram showing a driving device for a plasma display according to a second embodiment of the present invention. As shown in the figure, it is only necessary that the inductance at the time of collection is smaller than the inductance at the time of charging. Therefore, a coil is placed between the main power supply high-side switch and the bidirectional switch as in the past, and the bidirectional switch is charged. A coil may be arranged only on the path.

Embodiment 3 In the first embodiment, the collection-side coil 91 is arranged in the collection path. However, this can be eliminated, and power can be similarly reduced without providing a coil in the collection path. FIG. 5 shows a circuit configuration. Although the peak value of the current becomes larger than in the case of the first embodiment, the switching loss increases. However, since the current flows faster, more current can be recovered by the capacitor 10 of the reactive power recovery circuit 1. The effect of the low power is equal or higher. It goes without saying that the switching operation timing is the same as in the first and second embodiments.

Embodiment 4 FIG. 6 is a circuit diagram showing a driving device for a plasma display according to a fourth embodiment of the present invention. The driver IC includes an odd-numbered column driver IC 31 sharing an odd-numbered column and an even-numbered column driver I sharing an even-numbered column.
The low voltage side power supply terminals are 71 on the odd column side and 72 on the even column side. Each of the low-voltage power terminals is connected via the power line separation switch 15, and one of the low-voltage power terminals 71 and 72 is not connected to the low-voltage power. The high voltage side power supply terminals 41 and 42 are connected and connected to the output terminal 2 of the reactive power recovery circuit 1. The reactive power recovery circuit 1
A coil 9 is disposed between the other end of the main power supply high-side switch 6 and the bidirectional switch, and the low voltage sides of the capacitors 101 and 102 are connected to low voltage side power supply terminals 71 and 72, respectively.

Considering the cell size of the plasma display, the capacitance existing between the address electrodes A1 to An is 5 times the capacitance existing between the address electrodes and the scanning electrodes.
10 times larger. Further, since the capacitance value between the adjacent address electrodes is very large, the capacitance value existing between the odd-numbered and even-numbered columns of the address electrodes is 2% of the total capacitance value viewed from the address electrode side of the plasma display panel. / 3. By separating the low voltage side power supply line at the timing of collecting the electric charge charged in the panel, the path flowing through the parasitic transistor is opened, so that the charge is made between the odd column and the even column. All of the charges do not flow to the low voltage side through the parasitic transistors K1 to Kn, but can flow to the reactive power recovery circuit 1 side and can be recovered. FIG. 7 shows the timing of each switch at that time. When the recovery switch 12 is turned on,
The power supply line separation switch 15 is turned off, and this is the column affected by the parasitic transistor.
The low-voltage power supply line on the side flowing through the high-side switch in C3 is opened. Also in the case of the fourth embodiment, the power consumption can be similarly reduced as compared with the conventional case.

Embodiment 5 Further, in the configuration of the first to fourth embodiments, as shown in FIG. 8, the period during which the address voltage is switched, the second half of the period during which the recovery switch 12 is on, and the period during which the charge switch 14 is on. In the first half, the high-side switches AH1 to AH of the driver IC3
By turning off both the low-side switch AL and the low-side switches AL1 to ALn, the potential of the high-voltage power supply terminal 4 of the driver IC 3 that has dropped at the time of recovery can be recovered. Arm short circuit in unstable operation of switch can be prevented,
Power loss can be reduced.

In the above description, the present invention has been described in connection with a driving device for a plasma display. However, it goes without saying that the present invention can be applied to a case where a pulse voltage is applied to other capacitive loads.

[0026]

Since the present invention is configured as described above, it has the following effects.

A collection side coil and a charging side coil are provided in a collection path and a charging path of the bidirectional switch, and the inductance value of the collection side coil is made smaller than that of the charging side.
Alternatively, by setting the inductance value of the recovery side coil to zero, the recovery current can flow quickly, and the driver I
The loss caused by flowing to the low voltage side through the C parasitic transistor can be reduced.

The driver ICs are divided into odd-numbered columns and even-numbered columns, and the low-voltage side power supply lines are separated and connected via power supply line separation switches. By turning off the power line separation switch, the power loss due to the parasitic transistor can be reduced.

Further, by providing a period in which both the high-side and low-side switches of the driver IC are turned off in the second half of the recovery period and the first half of the charging period, the potential of the high voltage side power supply terminal of the driver IC is lowered. This prevents the arm from being short-circuited, thereby preventing power loss.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a driving device of a plasma display according to a first embodiment of the present invention.

FIG. 2 is a timing chart of a switch according to the first embodiment of the present invention.

FIG. 3 is a diagram for explaining an effect obtained by an experiment.

FIG. 4 is a circuit configuration diagram showing a plasma display according to a second embodiment of the present invention.

FIG. 5 is a circuit diagram showing a plasma display according to a third embodiment of the present invention.

FIG. 6 is a circuit configuration diagram showing a plasma display according to a fourth embodiment of the present invention.

FIG. 7 is a timing chart of a switch according to a fourth embodiment of the present invention.

FIG. 8 is a timing chart according to Embodiment 5 of the present invention.

FIG. 9 is a circuit diagram showing a conventional plasma display driving device.

FIG. 10 is a circuit diagram showing an arrangement of a parasitic transistor existing in a general driver IC.

[Explanation of symbols]

1 reactive power recovery circuit, 2 output of reactive power recovery circuit,
3 driver IC, 44, 41, 42 high voltage side power supply terminal, 5 high voltage side power supply, 6 main power supply high side switch,
7, 71, 72 Low voltage side power supply terminal, 9 coils, 10
101,102 capacitor, 11,13 diode,
12 collection switch, 14 charging switch, 15 power line separation switch, 31 odd-numbered column driver IC, 32
Even row driver IC, 91 Recovery side coil, 92 Charging side coil.

Claims (7)

[Claims] A plurality of scanning electrodes and a plurality of address electrodes are arranged orthogonally, a display cell is formed at the intersection of the electrodes, and a push-pull type driver circuit is connected to each of the address electrode groups. A reactive power recovery circuit provided with a reactive power recovery circuit at a high voltage side power supply terminal or a low voltage side power supply terminal of the driver circuit group, wherein the reactive power recovery circuit comprises a high voltage side power supply and the high voltage side power supply. A first switch provided between the terminals, a switch group provided by branching between the first switch and the high voltage side power supply terminal, and a capacitor connected between the switch group and the low voltage side power supply. The switch group controls a recovery path and a charging path, and the recovery path includes a second switch, a first diode, and a first coil, and the charging path includes a third switch and a second switch. Die A driving apparatus for a plasma display, comprising an arm and a second coil, wherein the inductance of the first coil is smaller than the inductance of the second coil. 2. The method according to claim 1, wherein the collecting path is connected to the second switch and a first switch.
A driving device for a plasma display, comprising a diode only, and a third coil provided between a branch of the first switch and the high-voltage side power supply terminal and the switch group. 3. The method according to claim 1, wherein the collecting path is connected to the second switch and the first switch.
A driving device for a plasma display, comprising a diode only. 4. A one-line scanning cycle set in a push-pull type driver circuit group provided for each of said address electrodes and during a period in which a high-voltage switch and a low-voltage switch are switched. A first step of turning off a first switch to disconnect a high-voltage power supply from the driver circuit group; a first step in the first step period;
Immediately before the switches of the driver circuit group are switched, a second step of turning on the second switch and collecting the electric charge charged in the plasma display into the capacitor, and a latter half of the first step period. And, immediately after the switches of the driver circuit group are switched, the third switch is turned off and the third switch is turned on to charge the plasma display with the electric charge stored in the capacitor. Turning on and off the switch of the reactive power recovery circuit in the order of a step and a fourth step of turning on the first switch and setting a potential between the address electrode and the scanning electrode to a predetermined value. The driving device for a plasma display according to any one of claims 1 to 3. 5. The plasma display device according to claim 1, wherein a low-voltage power supply line connected to the low-voltage-side power supply terminals of odd-numbered columns and even-numbered columns of the address electrode group is separated.
A fourth switch is provided between the odd-numbered column low-voltage power supply line and the even-numbered column low-voltage power supply line, and the reactive power recovery circuit includes a first switch provided between the high-voltage power supply and the high-voltage-side power supply terminal.
A switch, a switch group connected between the first switch and the high-voltage-side power supply terminal via a coil and a first capacitor connected between the switch group and the odd-numbered low-voltage power supply line; , A second capacitor connected between the switch group and the even-numbered low-voltage power supply line,
The switch group controls a recovery path and a charging path, wherein the recovery path includes a second switch and a first diode, and the charging path includes a third switch and a second diode. Driving device for plasma display. 6. A one-line scanning cycle set in a push-pull type driver circuit group provided for each of said address electrodes and during a period in which a high-voltage switch and a low-voltage switch are switched. A first step of turning off a first switch to disconnect a high voltage power supply from the driver circuit group, and simultaneously turning off the fourth switch to separate the odd column low voltage power line and the even column low voltage power line And the first half of the first step period,
And a second step of turning on the second switch and collecting the electric charge charged in the plasma display into the first or second capacitor immediately before the switch of the driver circuit group is switched; In the latter half of the step period and immediately after the switches of the driver circuit group have been switched, the second switch is turned off and the third switch is turned on, and the plasma display is switched to the first or second switch. A third step of charging with the electric charge stored in the capacitor, turning on the first switch, and turning on the fourth switch to set the potential between the address electrode and the scanning electrode to a predetermined value The plasma display according to claim 4, wherein a switch of the reactive power recovery circuit is turned on and off in the order of the fourth step. Of the drive unit. 7. A period during which both the high-voltage switch and the low-voltage switch of the circuit group are turned off in the first half of the third step, or in the second step and the first half of the third step, according to claim 4 and 6. A driving device for a plasma display, wherein the driving device is provided.