KR100588016B1 - Method and apparatus for driving plasma display panel - Google Patents

Abstract

The present invention relates to a method and apparatus for driving a plasma display panel.

The driving method of the plasma display panel according to the present invention includes calculating the amount of video data in a previous frame, and controlling the set-down discharge by comparing the calculated amount of video data with a reference data level.

An apparatus for driving a plasma display panel according to the present invention includes an analyzer for calculating the amount of video data and comparing it with a reference data level, a controller for controlling a scan driver to apply a falling ramp waveform that varies according to the results of the analyzer, and And a scan driver for applying the variable falling ramp waveform according to a control signal of the controller.

Description

Method and apparatus for driving plasma display panel {METHOD AND APPARATUS FOR DRIVING PLASMA DISPLAY PANEL}             

1 is a plan view schematically showing an electrode arrangement of a conventional three-electrode AC surface discharge type plasma display panel.

FIG. 2 is a waveform diagram illustrating a method of driving a plasma display panel as shown in FIG. 1.

3 is a flowchart illustrating a process of varying a lower limit voltage of a falling ramp waveform according to the amount of video data of a previous frame.

4 is a waveform diagram illustrating a method of driving a plasma display panel according to a first embodiment of the present invention.

5 is a flowchart illustrating a process of varying a slope of a falling ramp waveform according to the amount of video data of a previous frame.

6 is a waveform diagram illustrating a method of driving a plasma display panel according to a second embodiment of the present invention.

7 is a flowchart illustrating a process of varying a lower limit voltage of a falling ramp waveform according to the amount of high grayscale data of a previous frame.

8 is a flowchart illustrating a process of varying a slope of a falling ramp waveform according to the amount of high grayscale data of a previous frame.

9 is a view showing a driving apparatus of a plasma display panel according to an embodiment of the present invention.

10 is a circuit diagram illustrating a scan driver according to first and third embodiments of the present invention.

11 is a circuit diagram illustrating a scan driver according to second and fourth embodiments of the present invention.

Description of the main parts of the drawing

11: Timing Controller 12: Data Driver

13 scan driver 14 sustain driver

15: driving voltage generator 16: analyzer

20: energy recovery circuit 30: falling ramp generation and set down voltage selection circuit

40: falling ramp generation and slope selection circuit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving method and a driving device of a plasma display panel, and more particularly to a driving method of a reset period for initializing a discharge cell.

Plasma Display Panel (hereinafter referred to as "PDP") is used to excite and emit phosphors by using ultraviolet rays generated when an inert mixed gas such as He + Xe, Ne + Xe, He + Xe + Ne is discharged. Will be displayed. Such PDPs are not only thin and large in size, but also have improved in image quality due to recent technology development.

Referring to FIG. 1, a discharge cell of a conventional three-electrode AC surface discharge type PDP has an address orthogonal to the scan electrodes Y1 to Yn and the sustain electrode Z, and the scan electrodes Y1 to Yn and the sustain electrode Z. Electrodes X1 to Xm are provided.

Subpixels for displaying any one of red, green, and blue are formed at the intersections of the scan electrodes Y1 to Yn, the sustain electrode Z, and the address electrodes X1 to Xm. The scan electrodes Y1 to Yn and the sustain electrode Z are formed on the upper substrate. A dielectric layer and an MgO protective layer are stacked on the upper substrate. The address electrodes X1 to Xm are formed on the lower substrate. In the lower substrate, partition walls are formed to prevent optical and electrical interference between horizontally adjacent cells. Phosphors are excited on the lower substrate and the partition walls to be excited by vacuum ultraviolet rays and emit visible light. An inert mixed gas such as He + Xe, Ne + Xe, He + Xe + Ne is injected into the discharge space between the upper substrate and the lower substrate.

The PDP is time-divisionally driven by dividing one frame into several subfields having different number of emission times in order to implement grayscale of an image. Each subfield is divided into a reset period for initializing the full screen, an address period for selecting a scan line and selecting a cell in the selected scan line, and a sustain period for implementing gray scale according to the number of discharges. For example, when 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 SF1 to SF8. As described above, each of the eight subfields SF1 to SF8 is divided into an initialization period, an address period, and a sustain period. The initialization period and the address period of each subfield are the same for each subfield, while the sustain period and the number of sustain pulses allocated thereto are 2 ⁿ (n = 0,1,2,3,4,5,6) in each subfield. , 7).

2 illustrates a driving waveform for driving the PDP as shown in FIG. 1.

Referring to FIG. 2, the driving method of the PDP as shown in FIG. 1 is divided into a reset period for initializing a cell, an address period for selecting a discharge cell, and a sustain period for gradation expression.

The reset period is divided into a setup period in which the rising ramp waveform Rup is applied and a set down period in which the falling ramp waveform Rdown is applied.

At the beginning of the reset period, a rising ramp waveform Rup in which the voltage gradually rises from the sustain voltage Vs to the setup voltage Vsetup is applied to all the scan electrodes Y simultaneously. While the rising ramp waveform Rup is supplied to the scan electrodes Y, 0 [V] is applied to the sustain electrodes Z and the address electrodes X. Setup that causes the formation of wall charges between the scan electrode (Y) and the address electrode (X) and between the scan electrode (Y) and the sustain electrode (Z) in the cells of the full screen by the rising ramp waveform (Rup). Discharge occurs. Following the rising ramp waveform Rup, a falling ramp waveform Rdown in which the voltage falls from the sustain voltage Vs to the negative voltage -Vy is simultaneously applied to the scan electrodes Y. While the falling ramp waveform Rdown is supplied to the scan electrodes Y, the positive sustain voltage Vs is applied to the sustain electrodes Z, and 0 [V] is applied to the address electrodes X. . Due to the falling ramp waveform Rdown, almost no light is generated between the scan electrode Y and the sustain electrode Z, and a setdown discharge occurs as an erase dark discharge that causes the wall charges to be erased. As a result of this set-down discharge, excess wall charges are erased among the wall charges accumulated on each electrode (X, Y, Z) during setup discharge, so that wall charges remain uniformly in all cells.

In the address period, a negative scan pulse scp is applied to the scan electrodes Y, and a positive data pulse dp is applied to the address electrodes X in synchronization with the scan pulse scp. The sustain electrodes Z are supplied with the positive Z bias voltage Vz lower than the positive sustain voltage during the address period. After the reset period, in the state where the gap voltage is adjusted to be close to the discharge start voltage, the scan electrode Y and the address electrode in the on-cells to which the scan voltage scp and the data voltage dp are applied. Since the potential difference between (X) exceeds the discharge start voltage, address discharge occurs between the electrodes. The primary address discharge between the scan electrode (Y) and the address electrode (X) generates priming charged particles in the cell to induce a secondary discharge between the scan electrode (Y) and the sustain electrode (Z). In the discharge cells addressed, positive (+) wall charges are formed on the scan electrode (Y), and negative (-) wall charges are formed on the sustain electrode (Z).

In the sustain period, sustain pulses are alternately applied to the scan electrodes Y and the sustain electrodes Z. FIG. In the cells in which the discharge occurred in the address period, the sum of the wall potential due to the wall charge and the potential difference due to the sustain pulse becomes equal to or more than the discharge start voltage, and thus the discharge occurs between the scan electrode Y and the sustain electrode Z.

In such a driving PDP, address discharge and sustain discharge can be stably generated only if desired wall charges remain uniformly in all cells through the reset period. If the discharge cells are not initialized ideally through the reset period, a miswriting phenomenon or bright point discharge occurs.

In order to prevent this phenomenon, the discharge of the reset period should be induced stably. Since the reset discharge is followed by the sustain discharge of the previous frame, the initial condition of the wall charges during the reset discharge is determined according to the sustain discharge result of the previous frame.

If the amount of video data in one frame is large, a large number of cells have caused sustain discharge. In addition, in a frame to which large data is applied to express high gradation, the discharge is large and the amount of wall charges formed in the cells increases. In frames with many discharged cells, there is a statistically high gray level data.

In the opposite case, a small amount of video data in the previous frame results in fewer cells causing sustain discharge. In addition, the amount of wall charges formed in the cells is reduced in a frame in which small data is applied to express low gray levels.

When set-down discharge is performed with the same waveform in order to initialize the wall charge in the frame to which different data is applied, the wall charge is not uniformly erased and the driving margin for each cell is changed.

Accordingly, it is an object of the present invention to provide a method and apparatus for driving a PDP that can uniformly initialize the distribution of wall charges.

In order to achieve the above object, the driving method of the PDP according to the embodiment of the present invention is to calculate the amount of image signal on data in the previous frame, and to control the set-down discharge differently by comparing the calculated amount of video data with the reference data level It includes a step.

The controlling of the setdown discharge varies the lower limit voltage of the falling ramp waveform according to the video data amount.

The controlling of the setdown discharge lowers the lower limit voltage when the video data amount is greater than the reference data level and raises the lower limit voltage when the video data amount is smaller than the reference data level.

The controlling of the setdown discharge varies the slope of the falling ramp waveform according to the amount of video data.

The controlling of the set-down discharge increases the slope of the falling ramp waveform when the amount of video data is greater than the reference data level, and decreases the slope of the falling ramp waveform when the amount of video data is smaller than the reference data level.

According to an embodiment of the present invention, a PDP driving apparatus includes: an analyzer for calculating an amount of video data applied for discharge in a previous frame and comparing the amount of video data with a reference data level; A controller which controls the scan driver to apply a falling ramp waveform that is variable according to the analyzer result; And a scan driver for applying the variable falling ramp waveform according to a control signal of the controller.

The controller varies the lower limit voltage of the falling ramp waveform of set down discharge in accordance with the amount of video data.

The controller lowers the lower limit voltage of the falling ramp waveform if the amount of video data is greater than the reference data level, and raises the lower limit voltage of the falling ramp waveform if the amount of video data is less than the reference data level.

The controller varies the slope of the falling ramp waveform in accordance with the amount of video data.

The controller increases the slope of the falling ramp waveform if the amount of video data is greater than the reference data level, and decreases the slope of the falling ramp waveform if the amount of video data is less than the reference data level.

In order to achieve the above object, a method of driving a PDP according to another embodiment may include calculating an amount of video data for generating a discharge in a previous frame, and applying a high gray level applied to express a high gray level among the calculated video data. Calculating a data amount and controlling the set-down discharge differently by comparing the high gradation data amount with the reference data level.

The controlling of the setdown discharge varies the lower limit voltage of the falling ramp waveform according to the high grayscale data amount.

In the controlling of the set-down discharge, the lower limit voltage is lowered when the amount of high gradation data is greater than the reference data level, and the lower limit voltage is increased when the amount of high gradation data is smaller than the reference data level.

The controlling of the set-down discharge varies the slope of the falling ramp waveform according to the high gray scale data amount.

The controlling of the set-down discharge may increase the slope of the falling ramp waveform when the amount of high gradation data is greater than a reference data level, and decrease the slope of the falling ramp waveform when the amount of high gradation data is smaller than a reference data level. .

According to another exemplary embodiment of the present invention, an apparatus for driving a PDP includes an analyzer for calculating an amount of high gray level data applied for discharge at a high gray level and comparing the high gray level data amount with a reference data level. And a controller for controlling the scan driver to apply a variable ramp ramp waveform and a scan driver for applying the variable ramp ramp waveform according to a control signal of the controller.

The controller varies the lower limit voltage of the falling ramp waveform in accordance with the high gradation data amount.

The controller lowers the lower limit voltage of the falling ramp waveform if the amount of high gradation data is greater than the reference data level, and increases the lower limit voltage of the falling ramp waveform if the amount of high gradation data is less than the reference data level.

The controller varies the slope of the falling ramp waveform of the setdown discharge in accordance with the high gradation data amount.

The controller increases the slope of the falling ramp waveform when the amount of high gradation data is greater than the reference data level, and decreases the slope of the falling ramp waveform when the amount of high gradation data is smaller than the reference data level.

Other objects and features of the present invention in addition to the above object will be 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 11.

3 and 4 illustrate a method of driving a PDP according to a first embodiment of the present invention.

3 is a flowchart illustrating a method of varying the lower limit voltage of the falling ramp waveform Rdown according to the video data amount Da of the previous frame.

Referring to FIG. 3, the amount of video data Da applied to generate a sustain discharge from data of a previous frame is calculated. At this time, the video data amount Da is calculated by calculating the percentage of cells in which data is applied and actually lit, assuming a full white state in which all cells are turned on at 100 (%) (S1 to S2).

The calculated video data amount Da is compared with the reference data level (30% to 70%). In the first comparison step, if the amount of video data Da is 70 (%) or more, a falling ramp waveform (Rdown) having a lower limit voltage of -Vy3 is applied or goes to the next step (S3).

In the next comparison step, if the video data amount Da is 30 (%) or less, a falling ramp waveform Rdown having a lower limit voltage of -Vy1 is applied, or a falling ramp waveform Rdown having a lower limit voltage of -Vy2 is applied. S4)

That is, the reference voltage (-Vy2) is applied between the video data amount Da of the reference data level 30 (%) to 70 (%), and the lower limit voltage when the video data amount Da is larger than the reference data level. When the video data amount Da is smaller than the reference data level, the lower limit voltage is increased. Here, the range of the reference data level may vary depending on the driving environment of the PDP.

An embodiment of the present invention describes a method of calculating a video data amount and comparing it with a reference data level. For the same purpose as the present invention, an off data amount to which an image signal is not applied is calculated and compared with a new reference data level. You can also use the method.

4 is a waveform diagram illustrating a method of driving a PDP according to a first embodiment of the present invention.

Referring to FIG. 4, at the beginning of the reset period, a rising ramp waveform Rup in which the voltage gradually rises from the sustain voltage Vs to the setup voltage Vsetup is applied to all the scan electrodes Z simultaneously. While the rising ramp waveform Rup is supplied to the scan electrodes Z, 0 [V] is applied to the sustain electrodes Y and the address electrodes X. FIG. Due to the rising ramp waveform Rup, almost no light is generated between the scan electrode Y and the address electrode X and between the scan electrode Y and the sustain electrode Z in the cells of the full screen. A setup discharge occurs with a write dark discharge that causes As a result of this setup discharge, positive wall charges are accumulated on the address electrode X and the sustain electrode Z, and negative wall charges are accumulated on the scan electrode Y.

Following the rising ramp waveform Rup, a falling ramp waveform Rdown in which the voltage falls from the sustain voltage to the negative voltage is applied to the scan electrodes Y simultaneously. While the falling ramp waveform Rdown is supplied to the scan electrodes Y, 0 [V] is applied to the address electrodes X, and a positive voltage Vs is applied to the sustain electrodes Z.

According to the driving method of the PDP according to the first embodiment of the present invention, after the rising ramp waveform Rup, the falling ramp waveform Rdown, which changes the lower limit voltage according to the amount of video data of the previous frame, is applied to the scan electrodes Y. Apply simultaneously.

If the amount of video data Da in the previous frame is large, in order to make the erase discharge strong and stable, the discharge is strong by applying a falling ramp waveform Rdown having a lower limit voltage (-Vy3) lower than the reference lower limit voltage (-Vy2). However, it can be caused over a long time to sufficiently eliminate the wall charge.

On the contrary, if the amount of video data of the previous frame is small, the wall charge is generated by applying the falling ramp waveform Rdown having the lower limit voltage (-Vy1) higher than the reference lower limit voltage (-Vy2) to cause the discharge to occur in a weak and short time. Is excessively erased to prevent the potential difference between the scan electrode Y and the sustain electrode Z from occurring.

In the address period, a negative scan pulse scp is applied to the scan electrodes Y, and a positive data pulse dp is applied to the address electrodes X in synchronization with the scan pulse scp. The sustain electrodes Z are supplied with the positive Z bias voltage Vz lower than the positive sustain voltage during the address period. After the reset period, in the state where the gap voltage is adjusted to be close to the discharge start voltage, the scan electrode Y and the address electrode in the on-cells to which the scan voltage scp and the data voltage dp are applied. Since the potential difference between (X) exceeds the discharge start voltage, address discharge occurs at the electrodes. The primary address discharge between the scan electrode (Y) and the address electrode (X) generates priming charged particles in the cell to induce a secondary discharge between the scan electrode (Y) and the sustain electrode (Z). In the discharge cells addressed, positive (+) wall charges are formed on the scan electrode (Y), and negative (-) wall charges are formed on the sustain electrode (Z).

In the sustain period, sustain pulses are alternately applied to the scan electrodes Y and the sustain electrodes Z. FIG. In the cells in which the discharge occurred in the address period, the sum of the wall potential due to the wall charge and the potential difference due to the sustain pulse becomes equal to or more than the discharge start voltage, and thus the discharge occurs between the scan electrode Y and the sustain electrode Z.

5 and 6 illustrate a method of driving a PDP according to a second embodiment of the present invention.

5 is a flowchart illustrating a method of varying a slope of a falling ramp waveform Rdown according to the video data amount Da of a previous frame.

First, the amount of video data Da applied to generate a sustain discharge in the data of the previous frame is calculated. The calculation method of the video data amount Da is the same as in the first embodiment described above (S1 to S2).

The calculated video data amount Da is compared with the reference data level (30% to 70%). In the first comparison step, if the amount of video data Da is 70 (%) or more, a falling ramp waveform (Rdown) having a larger slope than the normal slope is applied, or the flow proceeds to the next step (S3).

In the next comparison step, if the video data amount Da is less than 30 (%), a falling ramp waveform (Rdown) whose slope is smaller than the normal slope is applied, or a falling ramp waveform (Rdown) having a normal slope is applied. Apply -Vy'2 (S4)

That is, when the video data amount Da is a reference data level of 30 (%) to 70 (%), a falling ramp waveform Rdown having a normal slope is applied -Vy'2, and the video data amount Da is If it is larger than the reference data level, the slope of the falling ramp waveform Rdown is increased, and if the video data amount Da is smaller than the reference data level, the slope of the falling ramp waveform Rdown is reduced. Also, the range of the reference data level may vary depending on the driving environment of the PDP. -Vy'1, -Vy'2, and -Vy'3 may also change depending on the driving environment of the PDP.

6 is a diagram illustrating a method of driving a PDP according to a second embodiment of the present invention.

In this embodiment, since the setup discharge, the address period, and the sustain period of the reset period are the same as in the foregoing first embodiment, description thereof will be omitted.

Referring to FIG. 6, in the reset period, a ramp ramp Rdown in which the voltage falls from the sustain voltage to the negative voltage is applied to the scan electrodes Y simultaneously after the ramp ramp Rup. While the falling ramp waveform Rdown is supplied to the scan electrodes Y, 0 [V] is applied to the address electrodes X, and a positive voltage Vs is applied to the sustain electrodes Y.

Subsequent to the rising ramp waveform Rup, the falling ramp waveform Rdown, whose slope varies according to the amount of on data of the previous frame, is simultaneously applied to the scan electrodes Y.

If the amount of video data of the previous frame is large, in order to strengthen the erase discharge, -Vy'3, which is a ramp ramp Rdown having a large slope, may be applied to cause the discharge to be instantaneously strong to sufficiently erase the wall charges.

On the contrary, if the amount of video data of the previous frame is small, the falling ramp waveform Rdown having a small slope is applied -Vy'1. That is, the discharge is caused to occur gradually to prevent the wall charges from being excessively erased.

The foregoing first and second embodiments have described a method of varying the falling ramp waveform according to the amount of video data of a previous frame. The amount of wall charge remaining in the video data for causing the discharge is high in the cells to which data for expressing a high gradation is applied, that is, cells discharged at high brightness. In particular, in these cells, nonuniformity of wall charge occurs more. Therefore, when there are many cells discharged with high gradation, it is necessary to make the erasure of the wall charges stronger.

7 and 4 are diagrams for describing a method of driving a PDP according to a third embodiment of the present invention.

FIG. 7 is a flowchart illustrating a method of varying the lower limit voltage of the falling ramp waveform Rdown according to the high grayscale data amount hDa of the previous frame.

Referring to FIG. 7, the amount of on data Da applied to generate a sustain discharge from data of a previous frame is calculated. When displaying an image of 256 gradations, cells displaying an image with 128 gradations or more among the calculated on data amounts Da are defined as high gradation data amounts hDa. (S1 to S2)

The calculated high gradation data amount hDa is compared with the reference data level (30% to 70%).

If the high gradation data amount hDa is 70 (%) or more in the first comparison step, a falling ramp waveform (Rdown) having a larger slope than the normal slope is applied, or the process proceeds to the next step (S3).

In the next comparison step, when the high gray level data amount hDa is 30 (%) or less, a falling ramp waveform (Rdown) having a lower limit voltage of -Vy1 is applied or a falling ramp waveform (Rdown) having a lower limit voltage of -Vy2 is applied. (S4)

That is, when the high gradation data amount hDa is greater than the reference data level, the reference voltage (-Vy2) is applied between 30 (%) to 70 (%), which is the reference data level. When the lower limit voltage is lowered and the high gradation data amount hDa is smaller than the reference data level, the lower limit voltage is increased.

The range of the reference data level may vary depending on the driving environment of the PDP. Also, the reference gradation for calculating the high gradation data amount hDa may also change according to the driving environment of the PDP.

The waveform of the driving method of the PDP according to the third embodiment of the present invention is the same as that of FIG. 4, which is the waveform of the driving method according to the first embodiment.

Description of the drawings showing the driving method of the PDP according to the third embodiment of the present invention is the same as the above-described first embodiment will be omitted.

8 and 6 are diagrams for describing a method of driving a PDP according to a fourth embodiment of the present invention.

Referring to FIG. 8, a method of varying the slope of the falling ramp waveform Rdown according to the high gray scale data amount hDa in the previous frame is as follows.

The method of calculating the high gradation data amount hDa is the same as in the above-described third embodiment.

First, the amount of on data Da applied to generate a sustain discharge from the data of the previous frame is calculated. When displaying an image of 256 gradations, cells displaying an image with 128 gradations or more among the calculated on data amounts Da are defined as high gradation data amounts hDa. (S1 to S2)

 The calculated high gradation data amount hDa is compared with the reference data level (30% to 70%). If the high gradation data amount hDa is 70 (%) or more in the first comparison step, a falling ramp waveform (Rdown) having a larger slope than the normal slope is applied, or the process proceeds to the next step (S3).

In the next comparison step, if the high gray level data (hDa) is less than 30 (%), the falling ramp waveform (Rdown) whose slope is smaller than the normal slope is applied, or the falling ramp waveform (Rdown) having the normal slope is applied. Apply -Vy'2 which is (S4).

That is, between the high gray level data amount hDa of 30 (%) to 70 (%) of the reference data level, -Vy'2 which is a falling ramp waveform Rdown having a normal slope is applied, and the high gray level data amount hDa is applied. Is larger than the reference data level, the slope of the falling ramp waveform Rdown is increased, and when the high gradation data amount hDa is smaller than the reference data level, the slope of the falling ramp waveform Rdown is decreased.

The range of the reference data level may vary depending on the driving environment of the PDP. The reference gradation for calculating the high gradation data amount hDa may also change according to the PDP driving environment.

Description of the drawings showing the method of driving the PDP according to the fourth embodiment of the present invention is the same as the above-described second embodiment will be omitted.

9 illustrates an apparatus for driving a PDP according to an embodiment of the present invention.

Referring to FIG. 9, an apparatus for driving a PDP according to an exemplary embodiment of the present invention includes an analyzer 16 that calculates an on data amount and a high gray level data amount of a previous frame and compares it with a reference data amount level, and address electrodes of the PDP. A data driver 12 for supplying data to (X1 to Xm), a scan driver 13 for driving the scan electrodes Y1 to Yn, a timing controller 11 for controlling each driver, A driving voltage generator 15 is provided to supply driving voltages to each driving unit.

The analyzer 16 calculates the on data amount and the high gradation data amount in one frame period, and compares the calculated on data amount and the high gradation data amount with a reference data level.

The scan driver 13 supplies the rising ramp waveform Rup to the scan electrodes Y1 to Yn as shown in FIG. 4 or 6 during the reset period under the control of the timing controller 11. Accordingly, a falling ramp waveform Rdown having a different voltage application period and voltage level is supplied to the scan electrodes Y1 to Yn. During the address period, the scan driver 13 sequentially supplies the scan pulse scp to the scan electrodes Y1 to Yn as shown in FIGS. 4 and 6. The scan driver 13 supplies the sustain pulse SUS to the scan electrodes Y1 to Yn as shown in FIG. 3 during the sustain period under the control of the timing controller 11.

The sustain driver 14 sustains the DC bias voltage as shown in FIG. 4 or 6 during the period in which the falling ramp waveform Rdown is supplied to the scan electrodes Y1 to Yn and the address period under the control of the timing controller 11. (Z) and alternately with the scan driver 13 during the sustain period to supply the sustain pulse SUS to the sustain electrodes (Z).

The timing controller 11 receives the vertical / horizontal synchronization signal and generates timing control signals CTRX, CTRY, and CTRZ required for each driving unit, and outputs the timing control signals CTRX, CTRY, and CTRZ to the corresponding driving units 12, 13, Supply to 14 controls each of the driving units 12, 13, 14. In particular, the timing controller 11 applies the scan driver 13 to apply a falling ramp waveform Rdown that varies according to the result of the analyzer comparing the on-data amount or high-gradation data amount of one frame with the reference data level. To control. The timing control signal CTRX supplied to the data driver 12 includes a sampling clock for latching data, a latch control signal, a switch control signal for controlling on / off time of the energy recovery circuit and the driving switch element. The timing control signal CTRY applied to the scan driver 13 includes a switch control signal for controlling on / off time of the energy recovery circuit and the driving switch element in the scan driver 13. The timing control signal CTRZ applied to the sustain driver 14 includes a switch control signal for controlling the on / off time of the energy recovery circuit and the driving switch element in the sustain driver 14.

The driving voltage generator 15 generates a setup voltage Vsetup of a rising ramp waveform, a falling ramp waveform Rdown, a scan voltage Vsc, a data voltage Vd, a sustain voltage Vs, and the like. At this time, the falling ramp waveform is a falling ramp waveform (-Vy1, -Vy2, -Vy3) or a falling ramp waveform (-Vy'1, -Vy ') whose slope is variable according to the amount of on-data or high gray scale data. 2, -Vy'3), etc. are applied.

FIG. 10 is a circuit diagram illustrating a scan driver in a PDP driving apparatus according to the first and third exemplary embodiments of the present invention.

Referring to FIG. 10, the scan driver 13 includes an energy recovery circuit 20, first to fourth switch elements S1, S2, S3 and S4, a falling ramp generation and a setdown voltage selection circuit 30. do.

The energy recovery circuit 20 recovers energy of reactive power not contributing to the discharge from the PDP and charges the recovered energy to the scan electrodes (Y). The energy recovery circuit 20 may be implemented by any known energy recovery circuit.

The first switch element S1 is connected to the setup voltage source Vsetup and the first node n1 to scan the setup voltage Vsetup via the first node n1 under the control of a timing controller 11 (not shown). It supplies to the electrode Y.

The second switch element S2 is connected to the scan bias voltage source Vsc and the second node n2 to receive the scan bias voltage Vsc through the second node n2 under the control of the timing controller 11. To feed.

The third switch element S3 is connected to the sustain voltage source Vs and the third node n3 to supply the sustain voltage Vs to the scan electrode via the third node n3 under the control of the timing controller 11. do.

The fourth switch element S4 is connected between the falling ramp generation and the setdown voltage selecting circuit 30 and the first node n1 that select any one of the first to third falling ramp voltage sources. The falling ramp generation and set-down voltage selection circuit 30 selects any one of the first to third falling ramp voltages under the control of the timing controller 11 and supplies them to the scan electrodes via the fourth switch element.

The lower limit voltage value of the setdown voltage depends on the video data amount Da or the high gradation data amount hDa.

That is, if the video data amount Da or the high gradation data amount hDa is larger than the reference data level, the setdown voltage selection circuit selects a setdown voltage having a lower limit voltage of -Vy3 and supplies it to the scan electrode under the control of the timing controller 11. do.

On the other hand, if the video data amount Da or the high gradation data amount hDa is smaller than the reference data level, the lower ramp voltage and the set-down voltage selection circuit 30 have a lower limit voltage of -Vy1 set-down voltage under the control of the timing controller 11. Select and supply to the scan electrode.

If the video data amount Da or the high gradation data amount hDa is in the reference data level range, a setdown voltage having a normal lower limit voltage of -Vy2 is selected and supplied to the scan electrode Y.

In the above operation, a scan voltage, a scan bias voltage, a sustain voltage, and a setdown voltage having a lower limit voltage are applied to the scan electrode Y.

FIG. 11 is a circuit diagram illustrating a scan driver according to second and fourth embodiments of the present invention.

Referring to FIG. 11, the scan driver 13 includes an energy recovery circuit 20, first to third switch elements, fifth switch elements S1, S2, S3, and S5, and a falling ramp generation and slope selection circuit ( 40).

The description of the operation of the first to third switch elements and the energy recovery circuit is the same as in the above-described embodiment.

The fifth switch element is connected between the slope selection circuit connected to the falling ramp waveform voltage source and the fourth node n4. The down ramp generation and slope selection circuit 40 controls the inclination of the down ramp waveform under the control of the timing controller 11 to apply the down ramp waveform to the scan electrode via the fifth switch element S5.

That is, when the video data amount Da or the high gradation data amount Da is larger than the reference data level, the falling ramp generation and the slope selection circuit 40 converts the slope largely from the normal setdown voltage under the control of the timing controller 11. The set down voltage is applied to the scan electrode (Y).

On the other hand, if the video data amount Da or the high gradation data amount hDa is less than the reference data level, the setdown voltage selection circuit scans the setdown voltage obtained by converting the gradient from the normal setdown voltage to a smaller value under the control of the timing controller 11. Applies to (Y).

If the video data amount Da or the high gradation data amount hDa is in the reference data level range, a falling ramp waveform having a normal slope of -Vy is applied to the scan electrode Y.

In order to change the slope of the setdown voltage as described above, the falling lamp selection circuit includes an RC integrator (not shown). Different inclination is to change the application period of the voltage, it can be implemented by adjusting the time constant (τ) value by varying the resistance value in the RC integrating circuit.

In this manner, a scan voltage, a scan bias voltage, a sustain voltage, and a setdown voltage having a varying slope are applied to the scan electrode Y.

As a result, the method and apparatus for driving a PDP according to an exemplary embodiment of the present invention may adjust the lower limit voltage or slope of the falling ramp waveform (Rdown) according to the amount of data of the previous frame or the amount of high grayscale data during setdown discharge, thereby maintaining the previous sustain. In the period of time, erasing discharges capable of initializing cells with nonuniform wall charge conditions to a uniform state are possible.

As described above, according to the driving method and the driving apparatus of the PDP according to the present invention, the cells can be uniformly initialized by varying the lower limit voltage or the slope of the falling ramp waveform according to the data amount of the previous frame. Therefore, the discharge in the address period and the sustain period can be stabilized to prevent erroneous discharge from occurring. That is, miswriting discharge and bright spot discharge can be reduced, and the display quality of the PDP can be improved.

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 (16)

A driving method of a plasma display panel in which a reset period for initializing a cell is driven by being divided into a setup period and a setdown period, Calculating an amount of video data of a previous frame; Controlling a set down voltage applied in a set down period according to the calculated video data amount; The lower limit voltage of the set down voltage is lowered if the calculated video data amount is greater than the reference data level, and the lower limit voltage of the set down voltage is increased if the calculated video data amount is smaller than the reference data level. How to drive the display panel. delete delete delete The method of claim 1, The controlling of the setdown voltage may include: And when the calculated video data amount is greater than the reference data level, the slope of the set down voltage is increased. When the calculated video data amount is smaller than the reference data level, the slope of the set down voltage is reduced. A method of driving a plasma display panel. delete delete The method of claim 1, And the video data is high gradation data for expressing a high gradation. A discharge cell is formed at an intersection of a first electrode, a second electrode, and a third electrode, and includes a reset period for initializing the discharge cell. An analyzer for calculating an amount of video data of a previous frame and comparing the amount of data with a reference data level; A first driver configured to apply a setup voltage and a setdown voltage variable according to a result of the analyzer during a reset period; And a controller for controlling the first driver in accordance with the result of the analyzer. The method of claim 9, And the controller changes the lower limit voltage of a set down voltage according to the amount of video data. The method of claim 10, And the controller lowers the lower limit voltage of the set down voltage when the video data amount is greater than the reference data level. The method of claim 10, And the controller increases the lower limit voltage of the set down voltage when the video data amount is smaller than the reference data level. The method of claim 9, And the controller changes the slope of the setdown voltage according to the amount of video data. The method of claim 13, And the controller increases the slope of the setdown voltage when the video data amount is greater than the reference data level. The method of claim 13, And the controller decreases the slope of the setdown voltage when the video data amount is smaller than the reference data level. The method of claim 9, And the video data is high gradation data for expressing a high gradation.

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