KR20160007806A - Organic light emitting diode display device and method thereof - Google Patents

Abstract

The present invention relates to an organic light emitting diode display device and a driving method thereof. The organic light emitting diode display device sets a precharge voltage to vary by considering a panel characteristics of a display panel, thereby improving display quality. The organic light emitting diode display device includes: the display panel having a plurality of pixels; a pixel driving circuit including a driving transistor inside the pixel to drive the pixel; a timing controller controlling the drive of the display panel; and a panel driving unit receiving a control signal from the timing controller and applying the control signal to the display panel. The timing controller senses at least one from a threshold voltage and mobility of the driving transistor to find a compensation value, and varies the precharge voltage accordingly.

Description

TECHNICAL FIELD [0001] The present invention relates to an organic light emitting diode (OLED) display device,

The present invention relates to an organic light emitting diode display and a driving method thereof.

The present invention relates to a panel driving circuit, and more particularly, to a panel driving circuit that drives a panel using an active pre-charge voltage so as to reduce energy loss that may occur during a pre-charge operation, To a panel driving circuit.

In recent years, a breakthrough has been made in the field of flat panel displays. Plasma displays, such as plasma display panels (PDPs), field emission displays (FEDs), and electroluminescent displays (EL), are typical examples of liquid crystal displays (LCDs).

Currently, an LCD is widely used as a video display device of a TV, a computer, or a mobile communication terminal. Such an LCD requires a backlight, which is not only heavy but also has a drawback that it is thick and has a slow response speed.

Therefore, there is an organic EL display device (or an organic light emitting diode (OLED)) which is attracting attention as a next generation image display device replacing an LCD.

The organic EL device OLED includes an extremely thin organic film layer having a thickness of 0.1 μm or less. When an electric current flows in the organic film layer, electrons and holes are recombined near the interface between the electron transport layer and the hole transport layer , And this light emission has an extremely fast response time of several hundreds or less.

As described above, the organic EL element OLED has a bipolar structure of an anode electrode (anode) and a cathode electrode (cathode). Due to the difference in the voltage-current characteristics of the individual organic EL elements OLED constituting the panel, .

The passive matrix method and the active matrix method are mainly used for the display means using the organic electroluminescent device (OLED), that is, the organic electroluminescent display device. In the passive matrix method, And a current is applied to a selected cathode line and an anode line to drive the organic EL element. The active matrix system is a driving method in which a thin film transistor (TFT) and a capacitor (Cst) are integrated in each pixel to maintain a voltage by a capacitor capacitance to be.

In the recent display panel market, demand for various display panels using OLED as well as LCDs is gradually increasing, and display panels are becoming larger and higher in resolution according to the demand of users. In order to drive a large-sized, high-resolution display panel corresponding to the user's demand, the driving capability for the panel must be increased. Also, in order to drive a large-sized and high-resolution panel, the number of channels increases, and in order to achieve a high resolution and a large size of the display panel, the number of data that can be processed by the panel driving circuit must be increased. As the driving capability required in the display driving circuit increases, the power consumed in the panel driving circuit increases due to the increased driving ability.

However, as the power consumed increases, the temperature inside the chip in which the panel driving circuit is implemented is increased. The temperature rise inside the chip deteriorates the performance of the panel driving circuit and causes a problem in that an error occurs in the output signal.

On the other hand, as means for suppressing the temperature rise inside the chip as described above, the panel driving circuit may include a precharging means and a charge sharing means. The pre-charge operation may reduce the burden on the driving of the panel driving circuit by pre-charging a predetermined voltage to the channel line before transferring the output voltage according to the data signal in the panel driving circuit.

However, in general, a voltage applied to a channel line (hereinafter referred to as a pre-charge voltage) at the time of performing a pre-charge operation uses a fixed fixed-size voltage, so that there is a problem that energy consumption is excessively consumed in the entire circuit. In addition, due to the fixed precharge voltage Vpre-c, it is not possible to reflect the change in the characteristics of the display panel, and thus it has been impossible to optimize the heating characteristics of the driver IC. If a pre-charge voltage (Vpre-c) inappropriate for the data voltage (Vdata) is applied, a display error may occur during driving the display panel. However, in the prior art, since there is no means for solving the above-mentioned problem, there is a deficiency in the pre-charge operation.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the conventional problems, and it is an object of the present invention to provide a method of compensating for a change in characteristics of a driving transistor included in each pixel outside a pixel, And an organic light emitting display device capable of varying a precharge voltage according to an applied data output voltage and a driving method thereof.

According to an aspect of the present invention, there is provided an organic light emitting diode display comprising: a display panel including a plurality of pixels each having a driving transistor for emitting a light emitting element according to a data output voltage; A panel characteristic sensing unit for sensing a characteristic of a driving transistor including at least one of a threshold voltage and a mobility of the driving transistor to generate sensing data; A panel characteristic value storage unit for storing sensed panel characteristic values; A comparison unit comparing the previous panel characteristic value stored in the panel characteristic value storage unit with the panel characteristic of the current frame; A precharge voltage calculation unit for calculating a precharge voltage according to a sensed panel characteristic value; A precharge voltage value storage unit for storing the calculated precharge voltage; A control unit for selecting a pre-charge voltage according to a comparison result of the comparison unit; And a data voltage generator for reflecting the selected precharge voltage.

According to another aspect of the present invention, there is provided a method of driving an organic light emitting diode display, including sensing a characteristic of a driving transistor including at least one of a threshold voltage and a mobility of a driving transistor, Sensing and storing panel characteristics; Sensing the panel characteristic and comparing the panel characteristic value with a previously stored panel characteristic value; Calculating and storing an appropriate precharge voltage according to the sensed panel characteristics; Selecting a precharge voltage of the current frame and a precharge voltage of a previous frame that are stored in advance according to the comparison result; Generating a data voltage by reflecting the selected precharge voltage; And applying the data voltage to the panel.

The organic light emitting diode display device and the driving method thereof according to the present invention have an effect of improving the heat generation by optimizing the heat generation of the driver IC by varying the output level of the precharge voltage according to the characteristic change of the display panel, The image quality such as noise that may be generated when a fixed pre-charge voltage that does not take account of the pre-charge voltage is prevented, thereby improving the image quality.

FIG. 1 is a schematic view for explaining an organic light emitting display according to an embodiment of the present invention. Referring to FIG.
2 is a diagram illustrating an exemplary configuration of an organic light emitting diode display device according to the present invention.
3 is a circuit diagram for explaining the pixel structure shown in FIG.
4 is a waveform diagram exemplarily showing driving waveforms in the first or second sensing period.
5 is a block diagram schematically showing the configuration of the timing controller of the first embodiment of the present invention.
6 is a block diagram schematically showing a configuration of a timing controller according to a second embodiment of the present invention.
7 is a graph showing a voltage change of a data output voltage according to a conventional precharge operation.
8 is a graph showing a voltage change of a data output voltage according to the precharge operation of the present invention.
9 is a diagram for adjusting a luminance value according to an image in the image analysis unit of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram schematically showing a configuration of a panel driving unit 2 according to an embodiment of the present invention. The OLED display device shown in Fig. 1 includes a timing controller 1, a panel driving unit 2, and a display panel 3. [ The key technical features of the present invention are accomplished through the timing controller 1, which is a conceptual term collectively referred to as a functional part for performing the operation of the present invention, rather than referring to a specific device. Therefore, although there are representations of blocks for performing other functions in the drawings or the detailed description of the present invention, they are not all integrated in the timing controller 1 in the present invention.

And FIG. 2 is a block diagram of the OLED display according to an embodiment of the present invention.

The panel driver 2 is further divided into a data driver 21, a gate driver 22, and a driving voltage supplier 23. The OLED display device shown in FIG. 1 applies the precharge voltage Vpre-c to the data line DL to increase the charging efficiency of the data voltage Vdata applied to the plurality of pixels P of the display panel 3, And then supplies the data voltage Vdata to the data line DL. Particularly, the embodiment compensates the data voltage Vdata according to the change of the panel characteristics such as the threshold voltage Vth and the mobility, and adjusts the precharge voltage Vpre- c to maximize the charging efficiency of the data voltage Vdata.

The display panel 3 includes a plurality of gate lines GL and a plurality of data lines DL. The gate line GL and the data line DL intersect each other to define a pixel region. Each pixel region is provided with a plurality of pixels P connected to the gate line GL and the data line DL.

Each of the plurality of pixels P is supplied with the precharge voltage Vpre-c and the data voltage Vdata provided from the data line DL in response to the scan pulse Scan provided from the gate line GL, (Vdata).

To this end, each of the plurality of pixels P may include an OLED as shown in FIG. 3 and a pixel driving circuit (PC) for driving the OLED.

The display panel 3 receives the data voltage Vdata. The data voltage Vdata includes a plurality of gate line groups G1 to Gm, a plurality of data lines D1 to Dn and a plurality of sensing lines M1 to Mm arranged in parallel to the plurality of data lines D1 to Dn, ) In the pixel region.

First, each of the data voltages Vdata includes a pixel driving circuit PC and an organic light emitting diode OLED. Each of the data voltages Vdata may be any one of a red pixel, a green pixel, a blue pixel, and a white pixel. One unit pixel for displaying one image may include an adjacent red pixel, a green pixel, and a blue pixel, or may include an adjacent red pixel, a green pixel, a blue pixel, and a white pixel.

In one embodiment, the pixel drive circuit PC may include a first switching transistor ST1, a second switching transistor ST2, a driving transistor DT, and a capacitor Cst. Here, the transistors ST1, ST2, and DT may be an a-Si TFT, a poly-Si TFT, an oxide TFT, an organic TFT, or the like as an N-type thin film transistor (TFT). The first switching transistor ST1 includes a gate electrode connected to the first gate line GLa, a first electrode connected to the adjacent data line Di, and a first node n1 which is the gate electrode of the driving transistor DT. And a second electrode connected to the second electrode. The first switching transistor ST1 is connected to the first node n1, that is, the driving transistor TR1, the data voltage Vdata supplied to the data line Di according to the gate-on voltage level supplied to the first gate line GLa, DT).

The second switching transistor ST2 includes a gate electrode connected to the second gate line GLb, a first electrode connected to the adjacent sensing line Mi and a second node n2 which is a source electrode of the driving transistor DT. And a second electrode connected to the second electrode. The second switching transistor ST2 supplies a reference voltage Vref (or a pre-charging voltage Vpre) supplied to the sensing line Mi according to the gate-on voltage level supplied to the second gate line GLb, To the node n2, that is, the drain electrode of the driving transistor DT.

The capacitor Cst includes first and second electrodes connected between the gate electrode and the source electrode of the driving transistor DT, i.e., the first and second nodes n1 and n2. The capacitor Cst charges the difference voltage between the voltages supplied to the first and second nodes n1 and n2, and then switches the driving transistor DT according to the charged voltage.

The driving transistor DT includes a gate electrode commonly connected to the second electrode of the first switching transistor ST1 and the first electrode of the capacitor Cst, a first electrode of the second switching transistor ST2 and the capacitor Cst, A source electrode commonly connected to the organic light emitting diode OLED, and a drain electrode connected to the first power supply line VDD. The driving transistor DT controls the amount of current flowing from the first power supply line VDD to the organic light emitting diode OLED by being turned on by the voltage of the capacitor Cst.

In the above-described embodiment, the pixel circuit PC is composed of three transistors and one capacitor. However, the number of transistors and capacitors constituting the pixel circuit PC may be variously modified.

The organic light emitting diode OLED emits a monochromatic light having a luminance corresponding to the data current Ioled by the data current Ioled supplied from the pixel driving circuit PC, that is, the driving transistor DT. To this end, the organic light emitting diode OLED is formed on an anode electrode (not shown) connected to the second node n2 of the pixel driving circuit PC, an organic layer (not shown) formed on the anode electrode, And a cathode electrode (not shown) to which the cathode power supply VSS is supplied.

At this time, the organic layer may have a structure of a hole transporting layer / an organic light emitting layer / an electron transporting layer or a structure of a hole injecting layer / a hole transporting layer / an organic light emitting layer / an electron transporting layer / an electron injecting layer. Further, the organic layer may further include a functional layer for improving the luminous efficiency and / or lifetime of the organic light emitting layer. The cathode electrode may be formed individually in each of the plurality of pixels P, or may be formed so as to be connected to the plurality of pixels P in common.

Each of the plurality of gate line groups G1 to Gm is formed in parallel with the first direction of the display panel 110, for example, the lateral direction. At this time, each of the plurality of gate line groups G1 to Gm consists of first and second gate lines GLa and GLb adjacent to each other. The first and second gate signals GSa and GSb are separately supplied from the panel driver 2 to the first and second gate lines GLa and GLb of the respective gate line groups G1 to Gm .

Each of the plurality of data lines D1 to Dn is formed to be parallel to the second direction of the display panel 110, for example, the longitudinal direction so as to intersect each of the plurality of gate line groups G1 to Gm. A data voltage Vdata is separately supplied to each of the data lines D1 to Dn through the panel driver 2. [

The data voltage Vdata supplied to each pixel P through the plurality of data lines D1 to Dn may be the data of which the characteristics of the driving transistor DT included in the pixel P are compensated Lt; / RTI > At this time, the characteristics of the driving transistor DT include at least one of the threshold voltage Vth of the driving transistor DT and the mobility of the driving transistor DT.

Each of the plurality of sensing lines M1 to Mn is formed in parallel with each of the plurality of data lines D1 to Dn. The reference voltage Vref is supplied to each of the sensing lines M1 to Mn from the panel driver 2. [ At this time, the reference voltage Vref is supplied to each sensing line M1 to Mn during the data charging period of each pixel P, and the precharging voltage Vpre is supplied to the threshold voltage of the driving transistor DT of each pixel P Is supplied to the sensing lines (M1 to Mn) during a part of the first sensing period sensing at least one of the voltage (Vth) and the mobility, or during a part of the second sensing period.

The first power supply line VDD is supplied with driving power having a first voltage level from the driving voltage supply unit 23 and the second power supply line VSS is supplied with a driving voltage from the driving voltage supply unit 23, Driving power having a voltage level is supplied.

The data driver 21 is connected to the plurality of data lines D1 to Dn and operates under the control of the timing controller 20. [ Specifically, the data driver 21 can drive each pixel P in the data charging period and the light emitting period during the first or second display period. The data driver 122 may drive each pixel P during the initialization period, the sensing voltage charging period, and the voltage sensing period during the first or second sensing period.

During the first or second display period, the data driver 21 supplies the reference voltage Vref to the sensing lines M1 to Mn every data charging period of each pixel P, and at the same time, Converts the input image DATA into a data voltage Vdata and supplies the data to the corresponding data lines D1 to Dn.

During the first or second display period, the data driver 21 supplies the precharging voltage Vpre to the sensing lines M1 to Mn for each sensing period and at the same time, the sensing data (DATA) supplied from the timing controller 20, Into data voltages Vdata for sensing and supplies the data voltages to the corresponding data lines D1 to Dn. Thereafter, the data driver 21 applies a voltage corresponding to the current flowing through the driving transistor DT of each pixel P to each of the sensing lines M1 to Mn (Vdata) by the precharging voltage Vpre and the sensing data voltage Vdata, The sensing lines M1 to Mn are floated. The data driver 122 senses the voltages charged in the sensing lines M1 to Mn and outputs the sensed voltage to the threshold voltage Vth of the driving transistor DT of each pixel P and the mobility And supplies the sensing data Dsen to the timing controller 21.

4 is a waveform diagram showing an example of a driving waveform in the first sensing period or the second sensing period. Referring to FIG. 4, the operation of the pixel P shown in FIG. 7 will be described with reference to FIGS. 6 and 7. FIG.

First, the panel driver 2 controls the driving timing of each of the data driver 21 and the gate driver 22 to set the pixel P in the initialization period t1, the sensing voltage charging period t2, And is driven in the period t3.

In the initialization period t1, the first and second gate signals GSa and GSb of the gate-on voltage level are supplied to the first and second gate lines GSa and GSb by the gate driver 22, The sensing data voltage Vdata converted from the sensing data DATA is supplied to the data line Di and the precharging voltage Vpre is supplied to the sensing line Mi by the data line driver 122. Thereby, the first and second switching transistors ST1 and ST2 of each pixel P are turned on by the first and second gate signals GSa and GSb of the gate-on voltage level, the voltage of the second node n2 is initialized to the precharging voltage Vpre so that the difference voltage Vdata between the data voltage Vdata and the precharging voltage Vpre is applied to the capacitor Cst, (Vdata-Vpre) is charged.

Next, in the sensing voltage charging period t2, the first and second gate signals GSa and GSb of the gate-on voltage level are supplied to the first and second gate lines GSa and GSb according to the gate driver 22, And the sensing data voltage Vdata is continuously supplied to the data line Di by driving the data driving unit 21 and the sensing line Mi is floated. Thus, in the sensing voltage charging period t2, the driving transistor DT is turned on by the sensing data voltage Vdata, and the voltage corresponding to the current flowing through the driving transistor DT, which is turned on, Lt; RTI ID = 0.0 > Mi. ≪ / RTI > At this time, the sensing line Mi is charged with a voltage corresponding to the threshold voltage Vth, which is one of the characteristics of the driving transistor DT.

Next, in the voltage sensing period t3, the first gate signal GSa of the gate-off voltage level is supplied to the first gate line GSa by the gate driver 22, and at the same time, the second gate signal GSa of the gate- The data line GSb is supplied to the second gate line GSb and the floating sensing line Mi is connected to the data driver 122 again. Accordingly, during the voltage sensing period t3, the data driver 122 senses the voltage charged in the connected sensing line Mi and supplies the sensing voltage Vth corresponding to the sensed voltage, that is, the threshold voltage Vth of the driving transistor DT And supplies the sensing data Dsen to the timing controller 1.

On the other hand, the timing controller 1 senses the threshold voltage Vth of the driving transistor DT of each pixel P in the first or second sensing period, The sensing can be re-run to sense the mobility. In this case, the timing controller 1 performs the same sensing process as described above, except that the first switching transistor ST1 of each pixel P is turned on only during the initialization period t1 and the sensing data voltage Vdata ) Is supplied only during the initialization period t1.

As a result, the gate-source voltage of the driving transistor DT rises due to the turn-off of the first switching transistor ST1 during the sensing voltage charging period t2 when the sensing operation is resumed so that the voltage of the capacitor Cst The gate-source voltage of the driving transistor DT is held by the driving transistor DT and the voltage corresponding to the current flowing through the driving transistor DT, i.e., the voltage corresponding to the mobility of the driving transistor DT is applied to the floating sensing line Mi Is charged. When the sensing operation is resumed, the data driver 21 senses the voltage charged in the sensing line Mi, that is, the voltage corresponding to the mobility of the driving transistor DT, and outputs the sensed voltage to the sensing data Dsen And provides it to the timing controller 1. [

5 is a graph showing a voltage change of a data voltage (Vdata) according to a conventional precharge operation. In the illustrated period A, a pre-charge period in which a pre-charge voltage Vpre-c fixed at a constant voltage level is supplied in advance before the output voltage according to the data signal is supplied. An operation for providing a voltage according to the data signal to the panel is performed in the section B shown in the following. As an example, if the preset precharge voltage Vpre-c is 6V and the voltage level of the data signal for implementing the gradation of the panel is 14V with respect to the data voltage Vdata at the current 0V voltage level state, A voltage variation is performed at a voltage level of 6V, and then, in the period B, a voltage variation of the remaining 8V is performed to produce a voltage level of 14V of the final data signal.

Meanwhile, FIG. 6 is a graph showing a voltage change of the data voltage (Vdata) according to the precharge operation according to the embodiment of the present invention. The steps of applying the precharge voltage Vpre-c and the remaining data voltage Vdata in the illustrated period A and period B are operated in the same manner. However, in the step of applying the pre-charge voltage Vpre-c, the precharge voltage Vpre-c is not a fixed value but a pre-charge voltage Vpre- The charge voltage Vpre-c also shows a variable range C that can be varied.

7, the panel characteristic sensing unit 10 in the timing controller 1 according to the embodiment performs sensing on the panel characteristics, that is, the threshold voltage Vth and the mobility of the driving transistor DT The panel characteristic sensing unit 10 transmits the panel characteristic information sensed from the panel characteristic sensing unit 10 to the comparison unit 14 and the comparison unit 14 compares the panel characteristic information sensed by the panel characteristic sensing unit 10 with the previous panel Is compared with the property values to determine whether they are the same or have changed. The precharge voltage calculator 12 determines a variable amount of the precharge voltage Vpre-c and the precharge voltage stored in the precharge voltage storage 13, The precharge voltage Vre-c of the current frame calculated by the precharge voltage calculation unit 12 is transmitted to the data output voltage generation unit 16, and the comparison unit Charge voltage value stored in the pre-charge voltage value storage unit 13 to the data output voltage generation unit 16 when there is no change in the panel characteristic value delivered from the pre-charge voltage storage unit 13. [

8 is a block diagram schematically showing the configuration of the timing controller 1 according to another embodiment of the present invention.

Referring to the block diagram of FIG. 8, an image analysis unit 17 is added to the block diagram of FIG. The image analysis unit 17 further has a technical feature that reflects the luminance change of the image information to generate the precharge voltage Vpre-c. The image analyzer 17 analyzes the image information to be applied to the display panel 3 in the current frame and influences the variation of the precharge voltage Vpre-c according to Gamma information in the frame.

FIG. 9 is a graph illustrating acquisition of Gamma information according to the Max luminance value of the frame using the image analysis unit 17 of FIG.

This may be achieved by using known technologies such as PLC (Peak Luminance Control) technology and APL (Adaptive Peak Luminance) technology, and a separate algorithm may be utilized for this.

A method for varying the precharge voltage Vpre-c while considering image analysis information will be briefly described with reference to FIGS. 8 and 9. FIG.

The image analyzer 17 analyzes the image information of the current frame and obtains Gamma information according to the Max luminance value of the corresponding frame. A variable range of the maximum voltage or the minimum voltage of the data voltage (Vdata) can be set based on the Gamma information by utilizing a conventionally known technology such as PLC (Peak Luminance Control) technology and APL (Adaptive Peak Luminance) The precharge voltage Vpre-C can be varied in the same ratio according to the variation of the threshold voltage Vdata.

Therefore, the most optimized pre-charge voltage Vpre-c can be applied by setting the precharge voltage Vpre-c in consideration of the luminance change amount with respect to the image information. This can optimize the heat generation of the driver IC, so that the effect of improving the heat can be obtained, and the image quality such as noise and the like can be prevented, thereby improving the image quality.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. Will be clear to those who have knowledge of.

1: timing controller 2: panel driver
3: display panel 10: panel characteristic sensing unit
11: Panel characteristic value storing unit 12: Pre-charge voltage calculating unit
13: Precharge phase value storage unit 14:
15: control unit 16: data voltage generating unit
21: Data driver 23: Gate driver
24:

Claims (7)

A display panel having a plurality of pixels;
A pixel driving circuit including a driving transistor in a pixel for driving the pixel;
A timing controller for controlling driving of the display panel; And
And a panel driver for receiving a control signal from the timing controller and applying the control signal to the display panel,
Wherein the timing controller senses at least one of a threshold voltage or a mobility of the driving transistor to find a compensation value and thereby varies the precharge voltage.
The method according to claim 1,
The timing controller
A panel characteristic sensing unit sensing a panel characteristic;
A panel characteristic value storage unit for storing the sensed panel characteristic value;
A pre-charge voltage calculator configured to set a pre-charge voltage in consideration of a change in panel characteristics;
A precharge voltage storage unit for storing the set precharge voltage;
A comparing unit comparing a current frame with a previous frame;
A control unit for selecting a pre-charge voltage according to a comparison result of the comparison unit; And
The organic light emitting diode display device including the data voltage generation unit reflecting the selected pre-
3. The method of claim 2,
Wherein the panel characteristic sensing unit senses at least one of a threshold voltage or a mobility of a driving transistor in a pixel and stores the sensed value in the panel characteristic value storage unit,
The comparison unit compares the panel characteristic of the current frame sensed by the panel characteristic sensing unit with the panel characteristic of the previous frame stored in the panel characteristic value storage unit,
The precharge voltage calculator calculates the precharge voltage according to the panel characteristic value sensed by the panel characteristic sensing unit, stores the precharge voltage in the precharge voltage value storage unit,
The controller selects the pre-charge voltage of the current frame and the pre-charge voltage of the previous frame stored in the pre-charge voltage value storage unit according to the result of the comparison unit,
Wherein the data voltage generating unit generates a data voltage by reflecting the pre-charge voltage value selected by the control unit. The method according to claim 2 or 3,
The timing controller may further include an image analysis unit for transmitting image analysis information to the pre-charge voltage calculation unit.
5. The method of claim 4,
The image analyzing unit analyzes image information of a current frame, acquires gamma information according to a maximum luminance value of the frame, and transmits the gamma information to the pre-charge voltage calculating unit.
The data voltage generator may vary the maximum voltage or the minimum voltage of the data voltage Vdata considering the image information,
The precharge voltage calculator may vary the precharge voltage Vpre-C at the same rate as the data voltage generating unit considering the image information further varies the maximum voltage or the minimum voltage of the data voltage Vdata. Organic light emitting diode display device
Sensing and storing panel characteristics of the organic light emitting diode display;
Sensing the panel characteristic and comparing the panel characteristic value with a previously stored panel characteristic value;
Calculating and storing a precharge voltage according to the sensed panel characteristics;
Selecting a pre-charge voltage of a current frame and a pre-charge voltage of a previous frame that are stored in advance according to the comparison result;
Generating a data voltage by reflecting the selected precharge voltage; And
Applying the data voltage to a panel; and driving the organic light emitting diode display device
The method according to claim 6,
Analyzing image data of a current frame to obtain gamma information according to a maximum luminance value of the frame;
Varying a maximum voltage or a minimum voltage of the data voltage (Vdata) according to the obtained gamma information;
And changing the maximum voltage or the minimum voltage of the data voltage (Vdata) to the precharge voltage (Vpre-C) at the same ratio.

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