KR100373531B1 - Energy Recovery Apparatus in Plasma Display Panel and Driving Method Thereof - Google Patents

Abstract

The present invention relates to a power recovery apparatus for a plasma display panel capable of reducing an initial charging time of a source capacitor.

The external capacitor included in the power recovery device of the plasma display panel of the present invention is initially charged before the capacitive load is charged using the voltage supplied from the sustain voltage source.

According to the present invention, since the source capacitor is initially charged by the sustain voltage, the initial charging time of the source capacitor can be reduced.

Description

Power recovery device for plasma display panel and driving method thereof {Energy Recovery Apparatus in Plasma Display Panel and Driving Method Thereof}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel, and more particularly, to an apparatus for recovering power of a plasma display panel to reduce an initial charging time of a source capacitor. The present invention also relates to a driving method using the power recovery device.

Plasma Display Panel (hereinafter referred to as "PDP") is a display device using visible light generated from a phosphor when ultraviolet light generated by gas discharge excites the phosphor. PDP is thinner and lighter than Cathode Ray Tube (CRT), which has been the mainstay of display means, and has the advantage of being able to realize high definition large screen. PDP is composed of a plurality of discharge cells arranged in a matrix form, one discharge cell constitutes a pixel of the screen.

1 is a perspective view showing a conventional AC surface discharge PDP.

Referring to FIG. 1, a discharge cell of a three-electrode alternating surface discharge type PDP is formed on a scan / sustain electrode 12Y and a common sustain electrode 12Z formed on an upper substrate 10, and a lower substrate 18. An address electrode 20X is provided. The upper dielectric layer 14 and the passivation layer 16 are stacked on the upper substrate 10 having the scan / sustain electrode 12Y and the common sustain electrode 12Z side by side. In the upper dielectric layer 14, wall charges generated during plasma discharge are accumulated. The protective layer 16 prevents damage to the upper dielectric layer 14 due to sputtering generated during plasma discharge and increases emission efficiency of secondary electrons. As the protective film 16, magnesium oxide (MgO) is usually used. The lower dielectric layer 22 and the partition wall 24 are formed on the lower substrate 18 on which the address electrode 20X is formed, and the phosphor 26 is coated on the surfaces of the lower dielectric layer 22 and the partition wall 24. The address electrode 20X is formed in the direction crossing the scan / sustain electrode 12Y and the common sustain electrode 12Z. The partition wall 24 is formed in parallel with the address electrode 20X to prevent ultraviolet rays and visible light generated by the discharge from leaking to the adjacent discharge cells. The phosphor 26 is excited by ultraviolet rays generated during plasma discharge to generate visible light of any one of red, green, and blue. Inert gas for gas discharge is injected into the discharge space provided between the upper and lower substrates 10 and 18 and the partition wall 24.

Referring to FIG. 2, a conventional AC surface discharge type PDP driving apparatus includes m / n discharge cells 1 having scan / sustain electrode lines Y1 to Ym, common sustain electrode lines Z1 to Zm, and A PDP 30 arranged in a matrix so as to be connected to the address electrode lines X1 to Xn, a scan / sustain driver 32 for driving the scan / sustain electrode lines Y1 to Ym, and a common sustain; The common sustain driver 34 for driving the electrode lines Z1 to Zm, the odd-numbered address electrode lines X1, X3, ..., Xn-3, Xn-1 and the even-numbered address electrode lines X2. First and second address drivers 36A and 36B for dividing and driving .X4, ..., Xn-2, Xn are provided. The scan / sustain driver 32 sequentially supplies scan pulses and sustain pulses to the scan / sustain electrode lines Y1 to Ym so that the discharge cells 1 are sequentially scanned in line units, and m × n The discharge in each of the four discharge cells 1 is continued. The common sustain driver 34 supplies a sustain pulse to all of the common sustain electrode lines Z1 to Zm. The first and second address drivers 36A and 36B supply image data to the address electrode lines X1 through Xn in synchronization with the scan pulse. The first address driver 36A supplies image data to the odd-numbered address electrode lines X1, X3, ..., Xn-3, Xn-1, and the second address driver 36B supplies the even-numbered address electrode lines ( Image data is supplied to X2, X4, ..., Xn-2, Xn).

In the AC surface discharge PDP thus driven, a high voltage of several hundred volts or more is required for the address discharge and the sustain discharge. Accordingly, in order to minimize the driving power required for the address discharge and the sustain discharge, a power recovery device is added to the scan / sustain driver 32 and the common sustain driver 34. The power recovery apparatus recovers the voltage charged in the scan / sustain electrode line (Y) and the common sustain electrode line (Z), and reuses it as a driving voltage at the next discharge.

3 is a diagram illustrating a conventional power recovery device installed at the front end of the scan / sustain driver.

Referring to FIG. 3, a conventional power recovery apparatus includes an inductor L connected between a panel capacitor Cp and a source capacitor Cs, and a parallel connection between the source capacitor Cs and the inductor L in parallel. The first and third switches S1 and S3 and the second and fourth switches S2 and S4 connected in parallel between the panel capacitor Cp and the inductor L are constituted. The panel capacitor Cp equivalently represents the capacitance formed between the scan / sustain electrode line Y and the common sustain electrode line Z. FIG. The second switch S2 is connected to the sustain voltage source Vsus, and the fourth switch S4 is connected to the ground voltage source GND. The source capacitor Cs recovers and charges the voltage charged to the panel capacitor Cp during the sustain discharge, and supplies the charged voltage to the panel capacitor Cp again. The source capacitor Cs has a very large capacitance value to charge a voltage of Vsus / 2 corresponding to half of the sustain voltage Vsus. The inductor L forms a resonance circuit together with the panel capacitor Cp. The first to fourth switches S1 to S4 control the flow of current. The power recovery device formed on the common sustain driver 34 is formed symmetrically with the scan / sustain driver 32 around the panel capacitor Cp.

4 is a timing diagram and waveform diagrams illustrating on / off timing of the switches illustrated in FIG. 3 and output waveforms of the panel capacitor.

3 and 4 will be described the operation of the power recovery device. First, it is assumed that the voltage charged between the scan / sustain electrode line Y and the common sustain electrode line Z, that is, the voltage charged in the panel capacitor Cp, before the T1 period is 0 volts. In addition, it is assumed that the source capacitor Cs is charged with a voltage of Vsus / 2. In the T1 period, the first switch S1 is turned on to form a current path from the source capacitor Cs to the first switch S1, the inductor L, and the panel capacitor Cp. At this time, the inductor L and the panel capacitor Cp form a series resonant circuit. Since the source capacitor Cs is charged with a voltage of Vsus / 2, the voltage of the panel capacitor Cp is increased to Vsus which is twice the voltage of the source capacitor Cs by the current charge / discharge of the inductor L in the series resonant circuit. Will rise. In the period T2, the second switch S2 is turned on. When the second switch S2 is turned on, the sustain voltage Vsus is supplied to the scan / sustain electrode line Y. The sustain voltage Vsus supplied to the scan / sustain electrode line Y prevents the voltage of the panel capacitor Cp from falling below the sustain voltage Vsus so that the sustain discharge occurs normally. At this time, since the voltage of the panel capacitor Cp rises to Vsus in the T1 period, the driving power supplied from the outside to minimize the sustain discharge is minimized. In the T3 period, the first switch S1 is turned off and maintains the sustain voltage Vsus supplied to the scan / sustain electrode line Y. In the T4 period, the second switch S2 is turned off and the third switch S3 is turned on. When the third switch S3 is turned on, a current path is formed from the panel capacitor Cp to the source capacitor Cs through the inductor L and the third switch S3 to charge the panel capacitor Cp. The voltage is recovered to the source capacitor Cs. As the panel capacitor Cp is discharged, the voltage of the panel capacitor Cp drops, and at the same time, the voltage of Vsus / 2 is charged to the source capacitor Cs. After the voltage of Vsus / 2 is charged to the source capacitor Cs, the third switch S3 is turned off and the fourth switch S4 is turned on. In the period T5 when the fourth switch S4 is turned on, a current path is formed from the panel capacitor Cp to the base voltage source GND, so that the voltage of the panel capacitor Cp drops to zero volts. In the T6 period, the state of the T5 period is maintained for a predetermined time. The AC drive pulses supplied to the actual scan / sustain electrode line Y and the common sustain electrode line Z are obtained by periodically repeating the operation process for the periods T1 to T6.

In order for the operation of the power recovery device to operate normally, the voltage of Vsus / 2 must be charged in the source capacitor Cs. When the power of the PDP is turned on, that is, when the PDP is turned on by the user, a voltage of 0 V is charged in the source capacitor Cs and the panel capacitor Cp. Thus, the second switch S2 is turned on to charge the source capacitor Cs with a voltage of Vsus / 2. When the second switch S2 is turned on, the panel capacitor Cp is charged by the voltage supplied from the sustain voltage Vsus. After the panel capacitor Cp is charged, the second switch S2 is turned off and the third switch S3 is turned on. When the third switch S3 is turned on, the voltage charged in the panel capacitor Cp is discharged, and the source capacitor Cs is charged by the voltage discharged from the panel capacitor Cp. In fact, this process is repeated a predetermined number of times to charge the source capacitor Cs with a voltage of Vsus / 2.

As such, the conventional power recovery device charges the voltage to the source capacitor Cs by using the voltage charged in the panel capacitor Cp, and thus, the initial charging time of the source capacitor Cs is consumed for several seconds. That is, the PDP can operate normally only after a few seconds have elapsed since the power is turned on.

Accordingly, an object of the present invention relates to a power recovery apparatus of a plasma display panel that can reduce the initial charging time of the source capacitor.

In addition, another object of the present invention relates to a driving method using the power recovery device.

1 is a perspective view showing a conventional AC surface discharge PDP.

FIG. 2 is a plan view showing an arrangement of electrode lines and discharge cells of the PDP shown in FIG. 1; FIG.

3 is a view showing a conventional power recovery device installed at the front end of the sustain drive unit.

FIG. 4 is a timing diagram and waveform diagram showing on / off timing of the switches shown in FIG. 3 and an output waveform of the panel capacitor. FIG.

5 is a timing diagram and waveform diagrams showing on / off timing of switches and a voltage charged to a source capacitor according to an embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

1: discharge cell 10: upper substrate

12Y: scan / sustain electrode 12Z: common sustain electrode

14,22 dielectric layer 16: protective film

18: lower substrate 20X: address electrode

24: partition 26: phosphor

30: PDP 32: scan / sustain drive unit

34: common sustain driver 36A: first address driver

36B: second address driver

In order to achieve the above object, the external capacitor included in the power recovery device of the plasma display panel of the present invention is initially charged before the capacitive load is charged using the voltage supplied from the sustain voltage source.

The external capacitor of the power recovery device driving method of the present invention includes an initial charging step before the capacitive load is charged using a voltage supplied from the sustain voltage source.

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 FIG. 5.

Hereinafter, the operation description of the power recovery device of the present invention will be described with reference to FIGS. 3 and 4.

5 is a view showing the initial operation of the power recovery apparatus according to an embodiment of the present invention.

Referring to FIG. 5, the second and third switches S2 and S3 are turned on when a power is turned on, that is, when the PDP is turned on by a user. When the second and third switches S2 and S3 are turned on, current paths are formed from the sustain voltage source Vsus to the second switch S2, the inductor L, and the third switch S3 to form a sustain voltage source ( Voltage is supplied from Vsus to the source capacitor Cs. That is, the source capacitor Cs is supplied with a voltage directly from the sustain voltage source Vsus at the time of initial charging. Therefore, the voltage of Vsus / 2 is charged to the source capacitor Cs for a short time. After the voltage of Vsus / 2 is charged to the source capacitor Cs, the second and third switches S2 and S3 are turned on. After the second and third switches S2 and S3 are turned on, the first switch S1 is turned on as shown in FIG. 4. When the first switch S1 is turned on, the voltage charged in the source capacitor Cs is supplied to the panel capacitor Cp. At this time, the voltage of the panel capacitor Cp rises to Vsus which is twice the voltage of the source capacitor Cs by the series resonant circuit formed by the inductor L and the panel capacitor Cp. After the panel capacitor Cp is charged with voltage, the second switch S2 is turned on. When the second switch S2 is turned on, the sustain voltage Vsus is supplied to the scan / sustain electrode line Y. The sustain voltage Vsus supplied to the scan / sustain electrode line Y prevents the voltage of the panel capacitor Cp from falling below the sustain voltage Vsus so that the sustain discharge occurs normally. After the sustain voltage Vsus is supplied to the panel capacitor Cp, the first switch S1 is turned on. After the first switch S1 is turned on, the second switch S2 is turned off and the third switch S3 is turned on. When the third switch S3 is turned on, the voltage charged in the panel capacitor Cp is recovered to the source capacitor Cs. That is, as the panel capacitor Cp is discharged, the voltage of the panel capacitor Cp is lowered, and at the same time, the voltage of Vsus / 2 is charged to the source capacitor Cs. After the voltage of Vsus / 2 is charged to the source capacitor Cs, the third switch S3 is turned off and the fourth switch S4 is turned on. When the fourth switch S4 is turned on, a current path is formed from the panel capacitor Cp to the base voltage source GND, so that the voltage of the panel capacitor Cp drops to zero volts. In contrast with the conventional power recovery device, the present invention charges the voltage of Vsus / 2 to the source capacitor Cs in a short time by using the sustain voltage Vsus during initial charging of the source capacitor Cs. The subsequent operation is the same as the conventional power recovery device.

As described above, according to the power recovery apparatus of the plasma display panel and the driving method thereof according to the present invention, the second and third switches are turned on during the initial charging of the source capacitor. When the second and third switches are turned on, a path is formed from the sustain voltage to the source capacitor. Therefore, since the source capacitor is initially charged by the sustain voltage, the initial charging time of the source capacitor can be reduced.

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.

Claims (5)

A sustain voltage source for supplying a sustain voltage to the scan / sustain electrode line and the common sustain electrode line, and recovers the voltage charged in the capacitive load formed between the scan / sustain electrode line and the common sustain electrode line and charges the external capacitor In the power recovery device, And the external capacitor is initially charged before the capacitive load is charged using the voltage supplied from the sustain voltage source. The method of claim 1, An inductor installed between the capacitive load and the external capacitor to form a resonant circuit with the capacitive load; First and second switches installed in parallel between the inductor and the external capacitor; And a third and a fourth switch provided in parallel between the inductor and the capacitive load. The method of claim 2, The third switch is connected to the sustain voltage source, And the fourth switch is connected to a base voltage source. The method of claim 3, wherein And second and third switches are turned on so that voltage can be supplied from the sustain voltage source to the external capacitor during initial charging of the external capacitor. A sustain voltage source for supplying a sustain voltage to the scan / sustain electrode line and the common sustain electrode line, and recovers the voltage charged in the capacitive load formed between the scan / sustain electrode line and the common sustain electrode line and charges the external capacitor In the power recovery method to And the external capacitor is initially charged before the capacitive load is charged using the voltage supplied from the sustain voltage source.