JP2000330515A - Power recovery circuit of plasma display device - Google Patents

Abstract

(57) Abstract: An object of the present invention is to stably operate a switch for controlling inflow and outflow of electric charge to and from a capacitor in a power recovery circuit of a plasma display device. SOLUTION: A power supply of a first high-side driver for driving a first switch circuit for controlling the inflow of electric charge to a first capacitor and a second switch circuit for controlling an outflow of electric charge from the first capacitor are driven. A power recovery circuit for a plasma display device, wherein the power is supplied from a power supply of a second high-side driver.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power recovery circuit used in a plasma display device used for displaying an image on a television receiver or a computer terminal.

[0002]

2. Description of the Related Art Conventionally, as a power recovery circuit of a plasma display device, the latest plasma display technology
(1996, published by ED Research, pages 107 to 11
1) is known. Here, the power recovery circuit of the conventional plasma display device will be briefly described, but the necessity and the operation principle of the power recovery circuit are described in detail in the above-mentioned reference, so that the power recovery circuit will be omitted. The driving method of the switch will be described.

FIG. 5 is a configuration diagram of a conventional power recovery circuit. In FIG. 5, switches S1 to S4, capacitor Css,
The portion composed of the coil L, the diodes D1 and D2, and the capacitor C, which resembles a plasma display panel as a capacitor, is the same as the power recovery circuit described in the aforementioned "Latest Plasma Display Technology". Here, the switches S1 to S4 include MOSFETs and I
Although it is common to use a GBT or the like as an electronic switch, a switch symbol will be used for simplicity.

In the AC type plasma display, it is necessary to charge / discharge the stray capacitance of the panel of the plasma display C and apply a voltage of Vo and 0 during a period of sustaining a discharge called a sustain period. That is, in FIG. 5, when the switch S2 is turned on under the condition that the switches S1, S3, S4 are turned off, the resonance between the coil L and the panel stray capacitance C causes the panel voltage to be reduced by the capacitor Cs.
It rises to about twice the voltage of s. At this time, the capacitor Cs
If the voltage of s is 1/2 of Vo, the panel voltage is Vo
It will rise to the vicinity. When the voltage rises to near Vo, the switch S3 is turned on to fix the voltage applied to the panel to Vo.

Next, when the applied voltage of the panel is set to 0,
The switches S2 and S3 that are on are turned off, and the switch S1 is turned on. Then, resonance occurs between the coil L and the panel stray capacitance C, the charge of the panel charged to the voltage Vo moves to the capacitor Css, and the panel voltage decreases to near zero. When the switch S4 is turned on, the panel voltage becomes zero.

By repeating the above operation, the voltage applied to panel C can be set to Vo or 0. In an ideal state, the voltage applied to the panel can be set to Vo or 0 by simply moving the charge between the capacitor Css and the stray capacitance C of the panel by means of resonance.
C × Vo, the energy required for charging and discharging the capacitor
× Vo becomes unnecessary. This is the basic concept of the power recovery circuit.

Next, a control method of the switches S1 and S2 will be described. Generally, the high side driver 2 is often used for controlling the switch S2. The high-side driver 2 has a built-in level shift circuit therein.
It is composed of a diode D3 that supplies a voltage of cc and separates the breakdown voltage. During the process of discharging the panel charge, the switch S4
Is turned on, a current flows through the path of Vcc → D3 → C1 → D2 → L → S4, and the capacitor C1 is charged to approximately Vcc. The high side driver 2 uses this capacitor C
The switch S2 is controlled using 1 as a power supply. When the switch S2 is turned on, the anode voltage of the diode D2 becomes equal to the terminal voltage of the capacitor Css, so that the potential of the capacitor C1 is raised and the diode D3 is turned off.

On the other hand, the control of the switch 1 is performed by clamping a control signal through a coupling capacitor Ck and a diode Dk without using a high-side driver. The reason why the high-side driver is not used for controlling the switch 1 is that the current outflow terminal side of the switch 1 is connected to the capacitor Css and the potential does not fluctuate.

[0009]

However, in the above configuration, the clamp time constant for generating the control signal of the switch 1 is long, and the discharge maintaining period is changed according to information such as the brightness of an image projected on the plasma display. If such an operation is performed, there may be a problem that the clamping is not reliably performed depending on the scene of the image.

[0010]

In order to solve the above-mentioned problems, a power recovery circuit of a plasma display device according to the present invention comprises a first switch circuit for driving a first switch circuit for controlling the flow of charge into a first capacitor. A second power supply for controlling the power supply of the high-side driver from the first capacitor;
Is supplied from the power supply of the second high-side driver that drives the switch circuit of FIG.

According to the present invention, the first switch circuit can be operated stably.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a power supply terminal of a first high-side driver for driving a first switch circuit for controlling the inflow of electric charge to a first capacitor, and to control the outflow of electric charge from the first capacitor. A power supply terminal of a second high-side driver for driving a second switch circuit to be connected is connected by a first diode, and a first high-side driver is supplied from a power supply of the second high-side driver through the first diode. Has the effect of being able to supply power.

Next, according to the present invention, a power supply terminal of a first high-side driver for driving a first switch circuit for controlling the inflow of charges to the first capacitor, and controlling the outflow of charges from the first capacitor. A power supply terminal of a second high-side driver for driving the second switch circuit is connected with a first diode, and a power supply terminal of the first high-side driver and a first power supply are connected with a second diode. Supplying the power of the first high-side driver from the power supply of the second high-side driver through the first diode, and supplying the power of the first capacitor through the second diode from the first power supply during startup when the voltage of the first capacitor is low. This has the function of supplying power to the first high-side driver.

Next, according to the present invention, a power supply terminal of a first high-side driver for driving a first switch circuit for controlling the flow of charge into the first capacitor, and controlling the flow of charge from the first capacitor. A power supply terminal of a second high-side driver that drives the second switch circuit is connected by a first diode, and a power supply terminal of the first high-side driver and a second power supply are connected to a third diode, a resistor, Are connected in series, and the power supply of the second high-side driver is connected to the first diode through the first diode.
Power supply for the high-side driver
Has the effect that power can be supplied from the power supply to the first high-side driver through the third diode and the resistor.

Next, according to the present invention, a power supply terminal of a first high-side driver for driving a first switch circuit for controlling the inflow of charge to the first capacitor, and controlling the outflow of charge from the first capacitor. M between the power supply terminal of the second high-side driver that drives the second switch circuit
A drain terminal and a source terminal of the OSFET are connected, a fourth diode is connected between the gate terminal and the source terminal of the MOSFET, a second capacitor is connected to the gate terminal, and the other terminal of the second capacitor is connected. The voltage is controlled by the control signal of the second high-side driver, and has an effect that the power of the first high-side driver can be supplied from the power of the second high-side driver through the MOSFET.

(Embodiment 1) Hereinafter, an embodiment of a power recovery circuit according to the present invention will be described with reference to FIG.

The present embodiment is a circuit for generating a pulse to be applied to a display panel. The circuit is connected to the electrodes of the display panel and is connected in series equivalently to the capacitance between the panel electrodes related to the electrodes of the display panel. A display including a charge / discharge circuit unit for generating a resonance current when charging / discharging the capacitance between the panel electrodes, and a voltage clamp unit connected to the electrodes of the display panel to keep the electrodes of the display panel at a constant potential. The charging / discharging circuit section includes a coil L for generating a resonance current when charging / discharging the inter-electrode capacitance C, and a charge / discharge circuit for charging / discharging the inter-electrode capacitance. Switches S1, S2, S for independently controlling the respective currents of the recovery capacitor Css for recovering power and the resonance current in charging and discharging of the capacitance C between the panel electrodes.
3, S4, coil L, power recovery capacitor Cs
s and switches S1 to S4 are connected in series, and the voltage clamp unit is connected between a power supply switch connected between an electrode of the display panel and a power supply line, and connected between an electrode of the display panel and a ground line. And a grounding switch.

In FIG. 1, S1 to S4 are MOSFE
It is an electronic switch such as T, IGBT, etc., and is simply called a switch using a switch symbol for easy understanding. L is a coil, D1 to D4 are diodes, C1, C
2. Css is a capacitor, C is a capacitor that resembles a plasma display panel as stray capacitance, and 1 and 2
Is a high-side driver with a built-in level shift circuit. By controlling the switches S1 to S4, the panel stray capacitance C
The operation of charging / discharging is described in the conventional example, and will not be described.

The method of controlling the switch 2 using the capacitor C1 as a power supply is the same as in the conventional example. In this embodiment, the switch 1 is controlled using the high-side driver 1, the diode D4, and the capacitor C2. Switch S
2 turns on, the anode voltage of the diode D2 becomes equal to the terminal voltage of the capacitor Css.
The potential of 1 is raised and the diode D3 is turned off. Then, a current flows in a path of C1, D4, C2, and S2, and the charge of the capacitor C1 moves to the capacitor C2. Therefore, the switch S1 can be controlled using the capacitor C2 as a power supply.

According to this configuration, the power supply for controlling the switch S1 can be the capacitor C2 based on the voltage of the capacitor Css, so that the switch S1 can be stably operated.
Can be controlled.

(Embodiment 2) Hereinafter, a second embodiment of the power recovery circuit of the present invention will be described with reference to FIG.

2 is the same as FIG. 1 described in the first embodiment, except for the diode D5, and a description thereof will be omitted. When the terminal voltage of the capacitor Css is lower than Vcc which is the first power supply at the time of startup, the capacitor C2 becomes Vcc →
It is charged along the route of D5 → C2 → Css. Diode D
Even if there is no 5, the capacitor C2 is charged, but in this case, since the current passes through the diodes D3 and D4, the voltage becomes lower by the forward voltage of the diode. The addition of the diode D5 increases the charging voltage of the capacitor C2, so that the starting characteristics are improved.

(Embodiment 3) Hereinafter, a third embodiment of the power recovery circuit of the present invention will be described with reference to FIG.

In FIG. 3, a diode D6 and a resistor R6
Except for this, the configuration is the same as that described in the first and second embodiments, and thus the description is omitted. When the voltage of the second power supply Vb is higher than the voltage of the first power supply Vcc, the capacitor C2 is charged from the diode D6 and the resistor R6, so that the starting characteristics are improved. Further, when the voltage of the second power supply Vb is higher than the terminal voltage of the capacitor Css, the capacitor C2 is not only turned on at the time of start-up but also at a steady state.
, The voltage drop at the diode D4 can be replenished, and the switch 1 can be controlled stably even when Vcc drops by that amount.

(Embodiment 4) A power recovery circuit according to a fourth embodiment of the present invention will be described below with reference to FIG. In FIG. 4, the MOSFET is inserted in place of the diode D4 of FIG. 1 described in the first embodiment. Diode D7 and capacitor C3 are MO
This is an element for controlling the SFET. Therefore, MO
Except for the SFET, the diode D7, and the capacitor C3, the configuration is the same as that described in the first embodiment, and the description is omitted. Vs2 that controls high-side driver 2 is LOW
At this time, the capacitor C3 is charged to a voltage close to Vcc through the diodes D3 and D7. Vs2 becomes HIGH and the high side driver 2 switches S
When 2 is turned on, the gate voltage of the MOSFET is raised, and the MOSFET is turned on. Then, the capacitor C1
The electric charge of the high-side driver 1 moves to the capacitor C2 through the MOSFET, and the high-side driver 1 can control the switch S1 using the capacitor C2 as a power supply. MOSFE
T has the same role as the diode D4 of FIG. 1, but the capacitor C has no forward voltage drop of the diode D4.
2 is almost equal to the terminal voltage of the capacitor C1, and the operation of the high-side driver 1 is stabilized.

[0026]

As described above, according to the power recovery circuit of the present invention, the power supply terminal of the first high-side driver that drives the first switch circuit that controls the flow of charge into the first capacitor; A power supply terminal of a second high-side driver that drives a second switch circuit that controls the outflow of charges from the first capacitor is connected by a first diode. The power of the first high-side driver can be supplied through one diode.

According to the power recovery circuit of the present invention, the power supply terminal of the first high-side driver for driving the first switch circuit for controlling the inflow of the electric charge to the first capacitor and the power supply terminal of the first capacitor. Second to control charge outflow
A power supply terminal of a second high-side driver for driving the switch circuit of the above is connected by a first diode, and a power supply terminal of the first high-side driver and the first power supply are connected by a second diode. Providing the power of the first high-side driver from the power supply of the second high-side driver through the first diode, and starting the first capacitor from the first power supply through the second diode at a low start-up voltage of the first capacitor. Power can be supplied to the high-side driver.

Further, according to the power recovery circuit of the present invention, the power supply terminal of the first high-side driver for driving the first switch circuit that controls the inflow of electric charge to the first capacitor, and the power supply terminal of the first capacitor. Second to control charge outflow
A power supply terminal of a second high-side driver for driving the switch circuit is connected by a first diode, and a power supply terminal of the first high-side driver and a second power supply are connected in series with a third diode and a resistor. The power supply of the second high-side driver supplies the power of the first high-side driver through the first diode, and the second power supply supplies the power of the first high-side driver through the third diode and the resistor. Power can be supplied to the side driver.

According to the power recovery circuit of the present invention, the power supply terminal of the first high-side driver for driving the first switch circuit for controlling the inflow of electric charge to the first capacitor, and the power supply terminal of the first capacitor. Second to control charge outflow
A drain terminal and a source terminal of a MOSFET are connected between a power supply terminal of a second high-side driver for driving the switch circuit, and a fourth diode is connected between a gate terminal and a source terminal of the MOSFET. A second capacitor is connected to the gate terminal, and the other terminal voltage of the second capacitor is controlled by a control signal of the second high-side driver. Power for the first high-side driver can be supplied through the MOSFET.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a power recovery circuit according to Embodiment 1 of the present invention.

FIG. 2 is a configuration diagram of a power recovery circuit according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a power recovery circuit according to Embodiment 3 of the present invention.

FIG. 4 is a configuration diagram of a power recovery circuit according to a fourth embodiment of the present invention.

FIG. 5 is a configuration diagram of a power recovery circuit in a conventional example.

[Explanation of symbols]

1, 2 High-side driver S1, S2, S3, S4 Electronic switch such as MOSFET, IGBT, etc. L Coil C Panel stray capacitance Css capacitor C1, C2, C3, Ck capacitor D1, D2, D3, D4, D5, D6, D7, Dk Diode R Resistance

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Keiji Shiote, Inventor 1006 Kazuma Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Takanori Matsumura 1-1-1, Matsushita-cho, Ibaraki-shi, Osaka Matsushita, Inc. F-term in Avicie Technology (reference) 5C058 AA11 BA01 BA35 5C080 AA05 BB05 DD03 DD09 DD26 FF03 FF09 JJ03

Claims (5)

[Claims] 1. A power supply of a first high-side driver for driving a first switch circuit for controlling the inflow of electric charge to a first capacitor, and a second switch circuit for controlling an outflow of electric charge from the first capacitor. A power recovery circuit for a plasma display device, wherein the power is supplied from a power supply of a second high-side driver to be driven. 2. The power recovery circuit according to claim 1, wherein a power supply terminal of the first high-side driver and a power supply terminal of the second high-side driver are connected by a first diode. 3. The power supply terminal of the first high-side driver and the power supply terminal of the second high-side driver are connected by a first diode, and the power supply terminal of the first high-side driver and the first power supply are connected to each other. 2. The power recovery circuit of the plasma display device according to claim 1, wherein the power recovery circuit is connected by a second diode. 4. A power supply terminal of the first high-side driver and a power supply terminal of the second high-side driver are connected by a first diode, and a power supply terminal of the first high-side driver and a second power supply are connected to each other. 2. The power recovery circuit of a plasma display device according to claim 1, wherein the power recovery circuit is connected in series with a third diode and a resistor. 5. A power supply between a power supply terminal of a first high-side driver and a power supply terminal of a second high-side driver.
A drain terminal and a source terminal of the OSFET are connected, a fourth diode is connected between the gate terminal and the source terminal of the MOSFET, a second capacitor is connected to the gate terminal, and the other terminal of the second capacitor is connected. 2. The power recovery circuit according to claim 1, wherein the voltage is controlled by a control signal of a second high-side driver.