KR100508254B1 - Energy Recovery Circuit and Driving Method Thereof - Google Patents

Abstract

The present invention relates to an energy recovery circuit using a booster driving method that can quickly operate the voltage rise and fall of the sustain pulse without reducing the driving efficiency, and a driving method thereof.

The energy recovery circuit includes an external capacitor and an energy recovery circuit; A panel capacitor; First and second switches disposed in parallel between the external capacitor and the panel capacitor; A first diode disposed between a first node and the first switch; A second diode connected between the first node and the second switch; An inductor connected to the first and second diodes via the first node and to the panel capacitor via a second node; A sustain voltage source for generating a sustain voltage; A third switch connected between the sustain voltage source and a second node; And a fourth switch connected between the second node and the base voltage source.

Description

Energy Recovery Circuit and Driving Method Thereof

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an energy recovery circuit of a plasma display panel (hereinafter referred to as "PDP"), and in particular, a booster driving method capable of quickly operating a voltage rising and falling of a sustain pulse without reducing driving efficiency. An energy recovery circuit and a driving method thereof are provided.

The biggest disadvantage of PDP is the high power consumption. That is, in order to reduce power consumption, it is necessary to increase luminous efficiency and minimize unnecessary energy consumption generated in the driving process without being directly related to discharge.

The AC PDP utilizes surface discharge occurring on the surface of the dielectric by applying an electrode to the dielectric. In this AC type PDP, the drive pulse has a high voltage of tens to hundreds [V] in order to sustain discharge from tens of thousands to millions of cells, and the frequency is more than several hundreds [k]. When such a driving pulse is applied in the cell, high capacitance charge / discharge occurs.

In this case, the capacitive load of the panel alone does not consume energy when charging / discharging occurs in the PDP. However, since a driving pulse is generated by using a DC power source, much energy loss occurs in the PDP. In particular, if an excessive current flows in the cell during discharge, the energy loss is greater. This energy loss results in an increase in the temperature of the switch elements, which in the worst case may destroy the switch element. The energy recovery circuit is included in the driving circuit of the PDP in order to recover energy generated unnecessarily in the panel.

1 is a circuit diagram showing a conventional energy recovery circuit.

Referring to FIG. 1, the energy recovery circuit proposed by 'Weber (USP-50811400)' includes first and second switches SW1 and SW2 connected in parallel between an external capacitor Css and an inductor L, And a third switch SW3 for supplying the sustain voltage Vs to the panel capacitor Cp, and a fourth switch SW4 for supplying the base voltage GND to the panel capacitor Cp.

First and second diodes D1 and D2 for limiting reverse current are connected in series between the first and second switches SW1 and SW2. The panel capacitor Cp equivalently represents the capacitance value of the panel, and Re and R_Cp represent the parasitic resistance of the electrode Re and the cell formed in the panel. The switches SW1, SW2, SW3, and SW4 are semiconductor switch devices, and are implemented as, for example, metal oxide semiconductor field effect transistor (MOSFET) devices.

Assuming that the external capacitor Css is charged with half the voltage of the sustain voltage Vs, the energy recovery circuit shown in FIG. 1 will be described with reference to FIG. 2 as follows. FIG. 2 illustrates an operation timing of the switches SW1, SW2, SW3, and SW4 in the energy recovery circuit of FIG. 1, and a voltage and a current during charging / discharging of the panel capacitor Cp.

When the first switch SW1 is turned on in the T1 section and the second, third and fourth switches SW2, SW3, and SW4 are turned off, the external capacitor Css is turned on. The voltage stored in is supplied to the inductor L via the first switch SW1 and the first diode D1. Then, since the inductor L constitutes an LC series resonant circuit together with the panel capacitor Cp, the panel capacitor Cp is charged with the resonance waveform, and the voltage charged in the panel capacitor Cp is the sustain voltage ( Rise to Vs). At this time, the positive resonant current I _L flowing through the inductor L starts to increase from zero as the voltage increases, reaches a predetermined value, and then decreases to zero again.

When the first switch SW1 is turned off and the third switch SW3 is turned on in the T2 section, the sustain voltage Vs is supplied to the panel capacitor Cp via the third switch SW3. At this time, the voltage applied to one side of the panel capacitor Cp maintains the sustain voltage Vs.

When the third switch SW3 is turned off and the second switch SW2 is turned on in the T3 section, the voltage across the panel capacitor Cp is inductor L, the second diode D2, and the second switch. Energy is recovered to the panel capacitor Cp via SW2. At this time, the voltage applied to one side of the panel capacitor Cp is reduced to zero at the sustain voltage Vs. In addition, the negative resonant current I _L flowing through the inductor L increases from zero as the voltage across one side of the panel capacitor Cp decreases, reaches a predetermined value, and then decreases to zero again. do.

When the second switch SW2 is turned off and the fourth switch SW4 is turned on in the T4 section, the voltage of the panel capacitor Cp drops to the base voltage GND.

As described above, since the voltage Vp across the panel capacitor Cp is charged / discharged by natural resonance in the conventional energy recovery circuit, the charge / discharge time becomes long.

Accordingly, it is an object of the present invention to provide an energy recovery circuit and a driving method capable of rapidly increasing and decreasing the voltage of a sustain pulse by using a booster method that charges an inductor instead of LC natural resonance.

In order to achieve the above object, the energy recovery circuit according to the present invention includes an external capacitor (Cp); A panel capacitor Css; First and second switches (SW1) disposed in parallel between the external capacitor and the panel capacitor; A first diode D1 disposed between a first node n1 and the first switch; A second diode (D2) connected between the first node and the second switch; An inductor (L) connected to the first and second diodes via the first node and to the panel capacitor via a second node; A sustain voltage source Vs for generating a sustain voltage; A third switch SW3 connected between the sustain voltage source and a second node n2; And a fourth switch SW4 connected between the second node and the base voltage source. In the ON state of the first and fourth switches, a closed loop is formed through the external capacitor, the first switch, the first diode, the inductor, the fourth switch, and the ground voltage source to charge current in the inductor. And the first and fourth switches are turned off to charge the panel capacitor with the reverse voltage appearing in the inductor while the sustain voltage source, the third switch, and the second switch are turned on. After forming a closed loop through the inductor, the second diode, the second switch, the external capacitor and the ground voltage source to charge the inductor, the second and third switches are turned off to turn off the inductor. Energy is recovered from the panel capacitor to the external capacitor with the reverse voltage appearing at. The energy recovery circuit includes a third diode (D3) connected between the first node and the base voltage source; And a fourth diode D4 connected between the first node and the sustain voltage source. The third switch is turned on after the panel capacitor is charged with the reverse voltage appearing in the inductor to maintain the voltage of the panel capacitor at the sustain voltage. The fourth switch is turned on after energy of the panel capacitor is recovered to the external capacitor by the reverse voltage appearing in the inductor, thereby maintaining the voltage of the panel capacitor at the base voltage. The driving method of the energy recovery circuit includes a closed loop via the external capacitor, the first switch, the first diode, the inductor, the fourth switch, and the base voltage source in the on states of the first and fourth switches. Forming and charging a current in the inductor; Turning off the first and fourth switches to charge the panel capacitor with a reverse voltage appearing in the inductor; In the inductor, a closed loop is formed through the sustain voltage source, the third switch, the inductor, the second diode, the second switch, the external capacitor, and the base voltage source in the on state of the second and third switches. Charging a current; And turning off the second and third switches to recover energy from the panel capacitor to the external capacitor with the reverse voltage appearing in the inductor. The driving method of the energy recovery circuit includes turning on the third switch to maintain the voltage of the panel capacitor at the sustain voltage after the panel capacitor is charged with the reverse voltage appearing in the inductor; And after the energy of the panel capacitor is recovered to the external capacitor due to the reverse voltage appearing in the inductor, turning on the fourth switch to maintain the voltage of the panel capacitor at the base voltage.

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Other objects and features of the present invention in addition to the above objects will become apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 3 to 9.

3 shows an energy recovery circuit according to the present invention.

Referring to FIG. 3, an energy recovery circuit according to an exemplary embodiment of the present invention includes first and second switches SW1 and SW2 connected in parallel between an external capacitor Css and an inductor L, and a panel capacitor Cp. ), A third switch SW3 for supplying the sustain voltage Vs, and a fourth switch SW4 for supplying the base voltage GND to the panel capacitor Cp.

In addition, the energy recovery circuit of the present invention discharges the third diode D3 for forming a current path when the voltage is supplied from the inductor L to the panel capacitor Cp, and the voltage charged in the panel capacitor Cp. And a fourth diode for forming a current path together with the inductor L.

First and second diodes D1 and D2 for limiting reverse current are connected in series between the first and second switches SW1 and SW2. An inductor L is connected to the first to fourth diodes D1 to D4 via a first node n1 and a panel capacitor Cp, third and fourth switches via a second node n2. (SW3, SW4). The third diode D3 is connected between the inductor L and the ground voltage source GND. The fourth diode D4 is connected between the inductor L and the sustain voltage source Vs. The panel capacitor Cp equivalently represents the capacitance value of the panel, and Re and R_Cp represent parasitic resistances of electrodes and cells formed in the panel. The switches SW1, SW2, SW3, and SW4 are used as semiconductor switch elements, for example, implemented as MOSFET elements.

Assuming that the external capacitor Css is charged with half the voltage of the sustain voltage Vs, the energy recovery circuit shown in FIG. 3 will be described with reference to FIG. 4 as follows. FIG. 4 is a diagram illustrating an operation timing of the switches SW1, SW2, SW3, and SW4, a voltage Vp applied to the panel capacitor Cp and a current flowing through the inductor L in the energy recovery circuit shown in FIG. 3. (I _L ) is shown.

The period before T1 represents an initial state, and the first, second and third switches SW1, SW2, and SW3 are turned off and the fourth switch SW4 is turned on to be applied to one side of the panel capacitor Cp. This is a section in which the voltage Vp is maintained at the ground voltage GND state.

In the T1 section, the fourth switch SW4 is maintained in the on state and the first switch SW1 is turned on. When the first switch SW1 is turned on, as illustrated in FIG. 5, the external capacitor Css, the first switch SW1, the first diode D1, the inductor L, and the fourth switch SW4 are turned on. A closed loop is formed which leads to the ground voltage source GND via. At this time, a current (voltage) is discharged from the external capacitor Css to charge the inductor L. Therefore, a predetermined current (voltage) is charged in the inductor L during the T1 period. Here, the section T1 is set until the inductor L is charged with a voltage (current) corresponding to approximately the sustain voltage Vs.

In the T2 section, the first and fourth switches SW1 and SW4 are turned off. When the first and fourth switches SW1 and SW4 are turned off, the reverse voltage is induced in the inductor L as shown in FIG. 6. At this time, since a closed loop is formed that leads to the third diode D3, the inductor L, the electrode Re formed in the panel, the panel capacitor Cp, and the base voltage source GND, a reverse voltage induced in the inductor L is formed. Is supplied to the panel capacitor Cp. Here, the panel capacitor Cp is charged (boost-up) at a high speed by the counter electromotive force of the inductor L. At this time, the third diode D3 is operated as a current path of the inductor L.

In the T3 section, the third switch SW3 is turned on. When the third switch SW3 is turned on, as shown in FIG. 7, the base voltage source (Vs), the third switch SW3, the electrode Re formed on the panel, and the panel capacitor Cp are connected to each other. A closed loop leading to GND) is formed. At this time, the sustain voltage Vs is supplied to the panel capacitor Cp via the third switch SW3, and the panel capacitor Cp causes sustain discharge while maintaining the sustain voltage Vs.

In the T4 section, the third switch SW3 is kept on and the second switch SW2 is turned on. When the second switch SW2 is turned on, as shown in FIG. 8, the sustain voltage Vs, the third switch SW3, the inductor L, the second diode D2, the second switch SW2, and the external capacitor ( A closed loop leading to the ground voltage source GND is formed via Css). At this time, a voltage corresponding to approximately half of the sustain voltage Vs is charged in the external capacitor Css.

In the period T5, the second and third switches SW2 and SW3 are turned off. When the second and third switches SW2 and SW3 are turned off, a reverse voltage is induced in the inductor L as shown in FIG. 9. In this case, a closed loop is formed that leads to the panel capacitor Cp, the electrode Re formed on the panel, the inductor L, the fourth diode D4, and the sustain voltage source Vs. Here, since the negative polarity of the inductor L is connected to the panel capacitor Cp, the voltage stored in the panel capacitor Cp is quickly discharged (boost-down) by the counter electromotive force of the inductor L. At this time, the fourth diode D4 is operated as a current path of the inductor L.

In the section after T5, the fourth switch SW1 is turned on. When the fourth switch SW1 is turned on, a closed loop connected to the panel capacitor Cp, the electrode Re formed on the panel, the fourth switch SW1, and the ground voltage source GND is formed. At this time, the voltage Vp applied to one side of the panel capacitor Cp is maintained at the ground voltage GND.

That is, in the present invention, since the voltage applied to one side of the panel capacitor Cp is charged and discharged by using the reverse voltage induced in the inductor L, a sustain pulse having a fast rise and fall time can be obtained.

As described above, the energy recovery circuit according to the present invention can operate the voltage rise and fall of the sustain pulse faster than the LC natural resonance by charging the charge to the inductor using the booster method. In addition, in the conventional energy recovery circuit, the boost-up / down driving may be performed by adjusting the switch driving pulse without changing the circuit.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

1 is a circuit diagram showing a conventional energy recovery circuit.

FIG. 2 is a drive waveform diagram of the energy recovery circuit shown in FIG.

3 is a circuit diagram showing an energy recovery circuit according to the present invention.

4 is a drive waveform diagram of the energy recovery circuit shown in FIG. 3;

5 is an operation circuit diagram of the energy recovery circuit shown in FIG. 3 in the inductor charging section.

6 is an operation circuit diagram of the energy recovery circuit shown in FIG. 3 in a boost-up period.

FIG. 7 is an operation circuit diagram of the energy recovery circuit shown in FIG. 3 in a sustain voltage sustain period. FIG.

8 is an operation circuit diagram of the energy recovery circuit shown in FIG. 3 in the inductor charging section.

9 is an operation circuit diagram of the energy recovery circuit shown in FIG. 3 in a boost-down period.

Claims (6)

An external capacitor Cp; A panel capacitor Css; First and second switches (SW1) disposed in parallel between the external capacitor and the panel capacitor; A first diode D1 disposed between a first node n1 and the first switch; A second diode (D2) connected between the first node and the second switch; An inductor (L) connected to the first and second diodes via the first node and to the panel capacitor via a second node; A sustain voltage source Vs for generating a sustain voltage; A third switch SW3 connected between the sustain voltage source and a second node n2; A fourth switch (SW4) connected between said second node and a ground voltage source; In the ON state of the first and fourth switches, a closed loop is formed through the external capacitor, the first switch, the first diode, the inductor, the fourth switch, and the ground voltage source to charge current in the inductor. And the first and fourth switches are turned off to charge the panel capacitor with the reverse voltage appearing in the inductor, while the sustain voltage source, the third switch, After forming a closed loop via the inductor, the second diode, the second switch, the external capacitor, and the base voltage source to charge a current in the inductor, the second and third switches are turned off to Energy recovery from the panel capacitor to the external capacitor with a reverse voltage appearing in the inductor Circuit. The method of claim 1, A third diode (D3) connected between the first node and the ground voltage source; And a fourth diode (D4) connected between said first node and said sustain voltage source. The method of claim 1, And the third switch is turned on after the panel capacitor is charged with the reverse voltage appearing in the inductor to maintain the voltage of the panel capacitor at the sustain voltage. The method of claim 1, And the fourth switch is turned on after energy of the panel capacitor is recovered to the external capacitor by a reverse voltage appearing in the inductor, thereby maintaining the voltage of the panel capacitor at a base voltage. An external capacitor Cp, a panel capacitor Css, first and second switches SW1 disposed in parallel between the external capacitor and the panel capacitor, disposed between the first node n1 and the first switch. A first diode D1, a second diode D2 connected between the first node and the second switch, connected to the first and second diodes via the first node and via a second node. An inductor (L) connected to the panel capacitor, a sustain voltage source (Vs) for generating a sustain voltage, a third switch (SW3) connected between the sustain voltage source and a second node (n2), the second node and a base voltage source In the driving method of the energy recovery circuit having a fourth switch (SW4) connected between, In the ON state of the first and fourth switches, a closed loop is formed through the external capacitor, the first switch, the first diode, the inductor, the fourth switch, and the ground voltage source to charge current in the inductor. Making a first step; Turning off the first and fourth switches to charge the panel capacitor with a reverse voltage appearing in the inductor; In the inductor, a closed loop is formed through the sustain voltage source, the third switch, the inductor, the second diode, the second switch, the external capacitor, and the base voltage source in the on state of the second and third switches. Charging a current; And recovering energy from the panel capacitor to the external capacitor with a reverse voltage appearing in the inductor by turning off the second and third switches. The method of claim 5, Maintaining the voltage of the panel capacitor at the sustain voltage by turning on the third switch after the panel capacitor is charged with the reverse voltage appearing at the inductor; Energy recovery of the panel capacitor after the energy of the panel capacitor is recovered to the external capacitor due to a reverse voltage appearing in the inductor, thereby turning on the fourth switch to maintain the voltage of the panel capacitor at a base voltage. How to drive a circuit.