KR20080024387A - Apparatus for driving plasma display panel and method thereof - Google Patents

Abstract

An apparatus and a method for driving a display panel are provided to reduce current stress due to an over current by storing current in a capacitor by turning on and off repeatedly. An apparatus for driving a display panel includes a capacitor(C), a driving switch(S), and a driving controller(42). The capacitor, which is connected to a panel capacitor formed by at least two electrodes, receives energy from a power supply unit and stores the received energy. The driving switch controls the apply of a source voltage from the power supply unit to the capacitor. The driving controller applies a driving control signal for controlling turn on and off to the driving switch, and stores the capacitor by the driving control signal, which is repeatedly turned on/ off in initial operation of the display panel.

Description

Apparatus for driving plasma display panel and method

1 is a perspective view showing an internal structure of a three-electrode surface discharge plasma display panel to which a driving device of a display panel according to the present invention is applied.

FIG. 2 is a block diagram schematically illustrating an apparatus for driving a plasma display panel for driving the plasma display panel of FIG. 1.

3 is a timing diagram illustrating an embodiment of a drive signal output from each driver of FIG. 2.

FIG. 4 is a block diagram schematically showing a driving apparatus of a plasma display panel capable of controlling charging at initial startup of a capacitor in a driving unit by a driving control unit according to a preferred embodiment of the present invention.

5 is a timing diagram schematically illustrating a driving control signal of a driving switch of a driving apparatus of the plasma display panel of FIG. 4.

<Explanation of symbols for the main parts of the drawings>

22: logic controller, 23: address driver,

24: X drive unit, 25: Y drive unit,

41: power supply unit, 42: drive control unit.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving apparatus for a display panel and a driving method thereof, and more particularly, a capacitor in which energy is stored for supplying sufficient energy for driving, and for driving a display panel by an on and off operation of a switching element. A driving device of a display panel and a driving method thereof.

As flat panel display devices, plasma display panels (PDPs), which are easy to manufacture large panels, have attracted attention. A plasma display panel is a display device that displays an image by using a discharge phenomenon. In general, a plasma display panel can be classified into a direct current type and an alternating current type according to the type of driving voltage. Due to the disadvantages, the development of the AC plasma display panel has been made a lot.

An AC plasma display panel includes a three-electrode AC surface discharge type plasma display panel having three electrodes and driven by an AC voltage. A typical three-electrode surface discharge type plasma display panel is composed of a multi-layered plate, which is spatially advantageous because it can provide a thinner, lighter, and wider screen than a conventional cathode ray tube (CRT).

As an example of a conventional plasma display panel, a three-electrode surface discharge plasma display panel, a driving apparatus thereof, and a driving method thereof are disclosed in US Patent No. 6,744,218 (name: Method of driving a plasma display panel in which the). width of display sustain pulse varies). Matters related to the plasma display panel, the driving apparatus, and the driving method disclosed in the above-mentioned US patent are included in the present specification, and a detailed description thereof will be omitted.

The plasma display panel includes a plurality of display cells formed in an area where the sustain electrode and the address electrode cross each other, and one display cell includes three discharge cells (red, green, and blue). The gray level of the image is expressed by adjusting the discharge state. The sustain electrode consists of an X electrode and a Y electrode.

In order to express the gray scale of the plasma display panel, one frame applied to the plasma display panel may be configured with eight subfields having different emission counts to express 256 gray scales. That is, in the case where the image is to be displayed with 256 gray levels, the frame period (16.67 ms) corresponding to 1/60 second is divided into eight subfields. There is a reset period, an address period, and a sustain discharge period in each of the sub-fields to drive the plasma display panel.

All discharge cells are initialized in the reset period. The discharge cells to be displayed are selected in the address period. In the sustain discharge period, display discharge occurs in discharge cells selected in the address period among all the discharge cells.

In the driving circuit for such a drive, a capacitor that can store a lot of energy for the supply of energy for discharge is used a lot. A large transient current can flow to charge these capacitors at initial startup of the drive circuit. This transient current causes the driving elements to be stressed when the power is turned on or off.

Therefore, when the elements are used for a long time, a problem may occur in reliability such that the driving elements are burned out.

An object of the present invention is to reduce the current stress due to the transient current flowing into the capacitor which is completely discharged during the initial startup, by charging the current while the on-off is repeated immediately before the application of the drive waveform at the initial startup. The present invention provides a driving device for a display panel and a driving method thereof.

According to an embodiment of the present invention, a panel capacitor is formed by at least two electrodes, and the display panel is driven by supplying power to the panel capacitor from a power supply unit. The panel capacitor is connected to the panel capacitor and receives and stores energy from the power supply unit. A capacitor; A driving switch controlling the application of power from the power supply to the capacitor; And a driving control unit configured to apply a driving control signal for controlling on or off to the driving switch, and to charge the capacitor by the driving control signal which is repeatedly turned on and off at the initial startup of the display panel. It provides a driving device for the panel.

A discharge cell is defined in an area where the X electrode and the Y electrodes and the address electrode intersect, and generate a drive control signal including an X drive control signal, a Y drive control signal, and an A drive control signal according to an image signal to be displayed. A logic controller configured to process the X driving control signal and apply the X driving control signal to the X electrodes, a Y driving unit processing the Y driving control signal and applying the Y driving control signal, and processing the A driving control signal It is preferable to have an address driver for applying to the address electrodes.

It is preferable that the capacitor and the driving switch are included in at least one of the logic controller, the X driver, the Y driver, and the address driver.

Preferably, the driving controller is included in the logic controller.

According to another aspect of the present invention, a panel capacitor is formed by at least two electrodes, and is supplied with a power supply to the panel capacitor from a power supply and driven, the capacitor connected to the panel capacitor and supplied with energy from the power supply and stored therein. And driving a display panel by a driving device including a driving switch for controlling the application of power from the power supply unit to the capacitor.

(a) initially charging the capacitor by a driving control signal which is repeatedly turned on and off at the initial startup of the display panel; And

(b) driving a display panel by supplying power to the panel capacitor;

It is preferable to drive a plurality of sub-fields according to respective gray weights for time-division gray scale display for each frame as a display period, and to operate by driving a reset period, an address period, and a sustain discharge period for each sub-field. .

Preferably, step (a) is performed before the first of the frames begins.

According to the present invention, by charging the current to the capacitor while repeating the on-off immediately before the application of the drive waveform during the initial startup, it is possible to reduce the current stress due to the transient current flowing into the capacitor that is completely discharged during the initial startup. .

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is an internal perspective view showing the structure of a three-electrode surface discharge plasma display panel.

Referring to the drawings, between the front and rear glass substrates 10 and 13 of the surface discharge plasma display panel 1, the address electrode lines A _{R1 to} A _Bm , the dielectric layers 11 and 15, and the Y electrode line (Y ₁ to Y _n ), X electrode lines (X ₁ to X _n ), fluorescent layer 16, partition wall 17, and magnesium monoxide (MgO) layer 12 as a protective layer are provided.

The address electrode lines A _{R1 to} A _Bm are formed in a predetermined pattern on the front side of the rear glass substrate 13. The lower dielectric layer 15 is applied to the entire surface in front of the address electrode lines A _{R1 to} A _Bm . In front of the lower dielectric layer 15, barrier ribs 17 are formed in a direction parallel to the address electrode lines A _{R1 to} A _Bm . These partitions 17 function to partition the discharge area of each discharge cell 14 and to prevent optical cross talk between each discharge cell 14. The fluorescent layer 16 is formed on the inner surface of the space formed between the lower dielectric layer 15 and the partition walls 17 formed on the rear glass substrate 13.

The X electrode lines X ₁ to X _n and the Y electrode lines Y ₁ to Y _n have a constant pattern on the rear side of the front glass substrate 10 to be orthogonal to the address electrode lines A _{R1 to} A _Bm . Is formed. Each intersection sets a corresponding discharge cell 14. Each X electrode line (X _{1 to} X _n ) and each Y electrode line (Y _{1 to} Y _n ) are combined with a transparent electrode line made of a transparent conductive material such as indium tin oxide (ITO) and a metal electrode line for increasing conductivity. Is formed. Here, the X electrode lines X ₁ to X _n become sustain electrodes in the respective discharge cells 14, and the Y electrode lines Y ₁ to Y _n correspond to scan electrodes in the respective discharge cells 14. And become an address electrode in the discharge cell 14 of each of the address electrode lines A _{R1 to} A _Bm .

In this case, scan electrodes are sequentially applied to select discharge cells to be displayed on the Y electrode lines. In addition, the X electrode lines become sustain electrodes that cause sustain discharge between the Y electrode lines.

FIG. 2 is a block diagram schematically illustrating an apparatus for driving a plasma display panel for driving the plasma display panel of FIG. 1.

Referring to the drawing, the driving device 20 of the plasma display panel 1 includes an image processor 21, a logic controller 22, an address driver 23, an X driver 24, and a Y driver 25. do. The image processor 21 converts an external analog image signal into a digital signal to generate internal image signals. The internal video signal may be 8 bits of red (R), green (G), and blue (B) image data, a clock signal, a vertical and horizontal synchronization signal, and the like. The logic controller 22 generates driving control signals S _A , S _Y , and S _X according to an internal image signal from the image processor 21.

In this case, the driving unit such as the address driver 23, the X driver 24, and the Y driver 25 receives input from the driving control signals S _A , S _Y , and S _X , and generates respective driving signals. The applied driving signal to each of the electrode lines.

That is, the address driver 23 applies the display data signal corresponding to the address signal S _A input from the logic controller 22 to the address electrode lines. The X driver 24 processes the X driving control signal S _X input from the logic controller 22 and applies the X driving control signal S _X to the X electrode lines. The Y driver 25 processes the Y driving control signal S _Y input from the logic controller 22 and applies it to the Y electrode lines.

3 is a timing diagram illustrating an embodiment of a drive signal output from each driver of FIG. 2.

Referring to the drawings, a unit frame for driving the plasma display panel (1 of FIG. 3) is divided into a plurality of subfields, and each subfield SF includes a reset period PR, an address period PA, and a sustain period. Divided into (PS).

First, in the reset period PR, a reset pulse consisting of a rising pulse and a falling pulse is applied to the Y electrodes Y ₁ , ..., Y _n , and the X electrodes X ₁ , ..., X _n. ) Is applied with a second voltage (bias voltage) from the time when the falling pulse is applied to perform reset discharge. All discharge cells are initialized by reset discharge. The rising pulse rises from the sustain discharge voltage (Vs) by the rising voltage (V _set ) and finally reaches the rising maximum voltage (V _set + Vs), and the falling pulse falls from the sustain discharge voltage (Vs) and finally falls The voltage V _nf is reached.

In the address period PA, scanning pulses are sequentially applied to the Y electrodes Y ₁ ,..., And Y _n , and A electrodes A ₁ ,..., A _m are displayed in accordance with the scanning pulses. The data signal is applied to perform address discharge. The discharge cells to be subjected to the sustain discharge occurring in the sustain period PS by the address discharge are selected. The scan pulse has a scan high voltage (Vsch) and sequentially has a scan low voltage (Vscl) whose voltage is lower than the scan high voltage (Vsch), and the display data signal is adapted to the scan low voltage (Vscl) of the scan pulse. It has a positive address voltage Va.

In the sustain period PS, a sustain pulse is alternately applied to the X electrodes X ₁ ,..., X _n and the Y electrodes Y ₁ ,..., Y _n to perform a sustain discharge. Luminance is expressed according to the gray scale weight allocated to each subfield by the sustain discharge. The sustain pulse has an alternating discharge voltage Vs and a ground voltage Vg.

On the other hand, it is possible that the drive signal different from that shown in FIG. 3 can be output from each driving unit of FIG.

In the driving circuit for such a drive, a capacitor that can store a lot of energy for the supply of energy for discharge is used a lot. A large transient current can flow to charge these capacitors at initial startup of the drive circuit. The transient current may cause the driving elements to be stressed when the power is turned on or off.

However, according to the present invention, by charging the current to the capacitor while repeating the on-off immediately before the application of the drive waveform during the initial startup, it is possible to reduce the current stress due to the transient current flowing into the capacitor that is completely discharged during the initial startup. have.

FIG. 4 is a block diagram schematically showing a driving apparatus of a plasma display panel capable of controlling charging at initial startup of a capacitor in a driving unit by a driving control unit according to a preferred embodiment of the present invention.

Referring to the drawings, the driving device 40 of the plasma display panel includes a panel capacitor Cp formed by at least two electrodes, and supplies power to the panel capacitor Cp from the power supply unit 41 to drive the display panel. The power supply part 41, the drive control part 42, and the drive part 43 are provided.

The power supply unit 41 supplies power to the entire display device including the driving device of the plasma display panel. The power supply unit 41 generates and supplies power required for the driving control unit 42 and the driving unit 43. The driver 43 applies the power according to each driving cycle of FIG. 3 to the panel capacitor Cp through the electrode lines, and includes a driving switch S and a capacitor C. Referring to FIG.

The capacitor C is connected to the panel capacitor Cp, and receives and stores energy from the power supply 41. The capacitor C is a device that stores a lot of energy for supplying energy for display discharge of the panel capacitor Cp. The drive switch S controls the application of power to the capacitor C from the power supply 41.

The drive control unit 42 applies a drive control signal for controlling ON or OFF to the drive switch S. FIG. As shown in FIG. 5, the driving control signal preferably includes a signal in which on and off are repeated before the normal driving signal TB is applied at the initial startup of the plasma display panel.

The driving control signal charges the capacitor step by step at time intervals. Therefore, it is possible to prevent the rapid transient current from flowing in order to charge the capacitor during the initial startup. Therefore, it is possible to prevent the drive switch S from being burned out due to a sudden transient current during initial startup.

Transient current flowing into the capacitor C, which is completely discharged at initial startup, is soft-started by a power supply unit such as a switching mode power supply (SMPS) to reduce current stress of the switching elements S. You can. However, in this case, there may be a block having a separate ground according to the design of the driving board, and there may be a block that is blocked by another block at the initial startup and cannot charge the capacitor. Therefore, in this case, a case where it is impossible to prevent a sudden transient current at the initial start-up may occur.

Therefore, in the present invention, as shown in the drive control signal shown in Fig. 5, the drive control for repeatedly turning on and off the drive switch S in the initial start-up period TA before the normal start period TB. By controlling by the signal, the driving input current can be gradually increased at time intervals. Therefore, it is possible to prevent the rapid current from being applied to the drive switch S in order to charge the capacitor at the initial startup. Therefore, it is possible to prevent the current stress from being applied to the switching element S due to the rapid transient current, thereby preventing the switching element from being burned out.

In the present embodiment, the driving unit 43 including the capacitor C and the driving switch S is composed of the logic control unit 22, the X driving unit 24, the Y driving unit 25, and the address driving unit 23 of FIG. 2. There may be at least one. In addition, the driving controller 42 may be included in the logic controller 22.

5 is a timing diagram schematically illustrating a driving control signal of a driving switch of a driving apparatus of the plasma display panel of FIG. 4.

Referring to the drawings, according to the driving method of the plasma display panel of the present invention, a panel capacitor (Cp of FIG. 4) is formed by at least two electrodes, and the panel capacitor (Cp) from the power supply (41 of FIG. 4) is formed. Drive with power. A capacitor (C of FIG. 4) connected to the panel capacitor Cp and receiving and storing energy from the power supply unit 41, and a driving switch S for controlling the application of power from the power supply unit 41 to the capacitor C. The plasma display panel is driven by the driving device 40 of FIG. 4. That is, the driving method of the plasma display panel is a driving method driven by the driving apparatus of the plasma display panel of FIG. 4.

The driving method of the plasma display panel includes an initial startup period (TA) for initially charging the capacitor (C) by a driving control signal which is repeatedly turned on and off at the initial startup of the plasma display panel, and the panel capacitor. And a normal driving period TB for supplying power to Cp to drive the plasma display panel normally. The initial start-up period TA is performed before the start of the first frame normally displayed by the image data.

The capacitor C is gradually charged at time intervals by the drive control signal in the initial startup period TA. Therefore, it is possible to prevent the rapid transient current from flowing in order to charge the capacitor during the initial startup. Therefore, it is possible to prevent the drive switch S from being burned out due to a sudden transient current during initial startup.

Therefore, by controlling the drive switch S by the drive control signal which repeats ON and OFF in the initial start-up period TA before the normal drive period TB, the drive input current has a time interval. Can increase slowly. Therefore, it is possible to prevent the rapid current from being applied to the drive switch S in order to charge the capacitor at the initial startup. Therefore, it is possible to prevent the current stress from being applied to the switching element S due to the rapid transient current, thereby preventing the switching element from being burned out.

According to the driving apparatus of the display panel and the driving method thereof according to the present invention, by charging the current to the capacitor while repeating the on-off immediately before the application of the driving waveform at the initial startup, the flow is introduced into the capacitor that is completely discharged during the initial startup Current stress due to transients can be reduced.

Although the present invention has been described with reference to one embodiment shown in the accompanying drawings, it is merely an example, and those skilled in the art may realize various modifications and equivalent other embodiments therefrom. I can understand. Accordingly, the true scope of protection of the invention should be defined only by the appended claims.

Claims (7)

The panel capacitor is formed by at least two electrodes, and supplies power to the panel capacitor from a power supply to drive the display panel. A capacitor connected to the panel capacitor and configured to receive and store energy from the power supply unit; A driving switch controlling the application of power from the power supply to the capacitor; And A display control panel configured to apply a driving control signal for controlling on or off to the driving switch and to charge the capacitor by the driving control signal which is repeatedly turned on and off at the initial startup of the display panel; Drive. The method of claim 1, The discharge cell is defined in the region where the X electrode and the Y electrode and the address electrode intersect, A logic controller for generating a drive control signal including an X drive control signal, a Y drive control signal, and an A drive control signal according to an image signal to be displayed, and an X that processes the X drive control signal and applies it to the X electrodes And a driving unit for processing the Y driving control signal and applying the same to the Y electrodes, and an address driving unit for processing the A driving control signal and applying it to the address electrodes. The method of claim 2, And the capacitor and the driving switch are included in at least one of the logic controller, the X driver, the Y driver, and the address driver. The method of claim 2, And a driving controller in the logic controller. A capacitor formed by at least two electrodes, the capacitor being connected to the panel capacitor and supplied with energy from the power supply and driven by supplying power to the panel capacitor from a power supply, and storing the energy from the power supply; To drive the display panel by a drive device including a drive switch for controlling the application of power to the capacitor, (a) initially charging the capacitor by a driving control signal which is repeatedly turned on and off at the initial startup of the display panel; And (b) driving a display panel by supplying power to the panel capacitor. The method of claim 5, For display of time-division grayscale for each frame as a display period, a plurality of sub-fields according to respective grayscale weights exist, and each of the sub-fields includes a reset period, an address period, and a sustain discharge period. Driving method. The method of claim 6, And the step (a) is performed before the first one of the frames starts.

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