KR101965674B1 - Driving method for organic light emitting display - Google Patents

Abstract

The present invention relates to an organic light emitting display device capable of improving the accuracy of degradation prediction data and capable of predicting deterioration even with a small amount of memory, and a driving method thereof.
An organic light emitting display device according to an embodiment of the present invention includes a display panel including a plurality of pixels including an organic light emitting diode and a pixel circuit for emitting the organic light emitting diode; A gate driver for supplying a scan signal and a drive voltage for driving the plurality of pixels; A data driver for supplying a data voltage and a reference voltage to the plurality of pixels during driving driving; A timing controller for controlling the gate driver and the data driver to operate; A memory in which degradation prediction model data is stored; And a deterioration predictor for filtering average stress data and performing a bit shift operation to generate average stress data of a current frame.

Description

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

The present invention relates to an organic light emitting display device, and more particularly, to an organic light emitting display device capable of improving the accuracy of degradation prediction data and capable of predicting deterioration even with a small amount of memory, and a driving method thereof.

1 is a circuit diagram illustrating a pixel structure of an organic light emitting display device according to a related art.

Referring to FIG. 1, each pixel of the display panel includes a switching TFT ST1, a driving TFT DT, a capacitor Cst, and an organic light emitting diode OLED.

The switching TFT ST1 is switched in accordance with a scan signal (scan or gate signal) supplied to the gate line GL and supplies the data voltage Vdata supplied to the data line DL to the driving TFT DT .

The driving TFT DT is switched in accordance with the data voltage Vdata supplied from the switching TFT ST1 to switch the data current flowing from the first driving power supply VDD supplied to the power supply line PL to the organic light emitting diode OLED (Ioled).

The capacitor Cst is connected between the gate terminal and the source terminal of the driving TFT DT and stores a voltage corresponding to the data voltage Vdata supplied to the gate terminal of the driving TFT DT, DT) of the signal.

The organic light emitting diode OLED is electrically connected between the source terminal of the driving TFT DT and the cathode power supply VSS and emits light by the data current Ioled supplied from the driving TFT DT.

Each pixel of the organic light emitting display device according to the related art uses a data current Vdata flowing from the first driving power supply VDD to the organic light emitting diode OLED by switching the driving TFT DT according to the data voltage Vdata. And controls the size of the organic light emitting diode OLED to display a predetermined image.

There is a problem that the threshold voltage Vth / mobility characteristic of the driving TFT DT varies depending on the pixel depending on the non-uniformity of the manufacturing process of the TFT. Accordingly, even when the same data voltage (Vdata) is applied to the driving TFT DT of each pixel in a general organic light emitting display device, there is a problem that a uniform image quality can not be realized due to a deviation of a current flowing through the organic light emitting diode OLED . To improve this, all the pixels are sensed before shipment of the product to compensate the threshold voltage (Vth) / mobility characteristic of the driving TFT (DT).

2 and 3 are diagrams for explaining a deterioration compensation method using the OLED deterioration prediction method according to the related art.

Referring to FIG. 2, even if all the pixels are compensated through initial compensation, if the driving for displaying an image is performed for a long time, the light efficiency of the organic light emitting diode OLED and the change in the threshold voltage / mobility of the driving TFT DT The brightness of the pixels is lowered and a deviation occurs. The degradation of the luminance of a pixel results in image quality nonuniformity such as afterimage, and a method for compensating internal compensation, external compensation and deterioration prediction has been proposed as a method for improving the image quality.

Referring to FIG. 3, the degradation prediction / compensation method estimates the degree of stress applied to OLED pixels due to image data and time lapse, compensates a data signal applied to OLED pixels according to the degradation prediction result, The problem of non-uniformity is solved.

The degradation prediction method according to the related art predicts the deterioration level by using the accumulated stress data according to the input image data. When the continuous driving is continued, the size of the accumulated stress data increases, The manufacturing cost is increased.

Also, in order to reduce the increase of the memory, there is a problem that the accuracy of the compensation data is lowered because cumulative stress data is generated with a limited bit and the cumulative number of times is proposed. Therefore, the use of low-accuracy compensation data degrades image quality and reduces the lifetime of the organic light emitting diode (OLED).

An object of the present invention is to provide an organic light emitting display device and a method of driving the same that can improve the accuracy of degradation prediction data.

An object of the present invention is to provide an organic light emitting display device capable of predicting deterioration even with a small memory use and a driving method thereof.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide an organic light emitting display device and a method of driving the same, which can prevent image quality deterioration due to driving time duration.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an organic light emitting display device and a driving method thereof that can prevent an increase in manufacturing cost due to application of a deterioration prediction compensation method.

Other features and advantages of the invention will be set forth in the description which follows, or may be obvious to those skilled in the art from the description and the claims.

According to an aspect of the present invention, there is provided an organic light emitting display device including: a display panel including a plurality of pixels including an organic light emitting diode and a pixel circuit for emitting the organic light emitting diode; A gate driver for supplying a scan signal and a drive voltage for driving the plurality of pixels; A data driver for supplying a data voltage and a reference voltage to the plurality of pixels during driving driving; A timing controller for controlling the gate driver and the data driver to operate; A memory in which degradation prediction model data is stored; And a deterioration predictor for filtering average stress data and performing a bit shift operation to generate average stress data of a current frame.

According to an aspect of the present invention, there is provided a method of driving an organic light emitting display device including a display panel including a plurality of pixels including a pixel circuit for emitting an organic light emitting diode, The method comprising: filtering average stress data according to image data of n frames and performing bit shift operation to generate average stress data of a current frame; Converting the frame count value into a bit value by approximating the frame count value, and generating a correction bit for correcting an error caused by the approximation of the frame count value; The number of input bits is shifted by a right bit to reduce the lower bits of the number of input bits or the number of input bits is left bit shifted to increase the lower bits of the number of input bits step; And compensating degradation of the organic light emitting diode formed in the plurality of pixels by using an average stress value obtained by performing a bit shift operation.

The organic light emitting display device and the driving method thereof according to the embodiment of the present invention can improve the accuracy of the degradation prediction data.

The organic light emitting display device and the driving method thereof according to the embodiment of the present invention enable precise deterioration prediction even with a small memory use.

The organic light emitting display device and the driving method thereof according to the embodiment of the present invention can prevent deterioration of image quality due to the duration of driving time.

The organic light emitting display device and the driving method thereof according to the embodiment of the present invention can prevent an increase in manufacturing cost due to the application of the deterioration prediction compensation method.

In addition, other features and advantages of the present invention may be newly understood through embodiments of the present invention.

1 is a circuit diagram illustrating a pixel structure of an organic light emitting display device according to a related art.
2 and 3 are diagrams for explaining a deterioration compensation method using the OLED deterioration prediction method according to the related art.
4 is a view schematically showing an organic light emitting display device according to an embodiment of the present invention.
5 is a circuit diagram illustrating a data driver and a pixel structure of an OLED display according to an embodiment of the present invention.
6 is a diagram showing a deterioration predictor according to an embodiment of the present invention.
FIG. 7 is a diagram showing the error correction unit shown in FIG. 6. FIG.
8 is a diagram for explaining an example in which an error occurs in a bit shift operation.
FIG. 9 is a diagram for explaining a method of correcting an error by a bit shift operation.
10 is a diagram for explaining the effect of increasing the accuracy of the degradation prediction data by applying the degradation prediction unit according to the embodiment of the present invention.

It should be noted that, in the specification of the present invention, the same reference numerals as in the drawings denote the same elements, but they are numbered as much as possible even if they are shown in different drawings.

Meanwhile, the meaning of the terms described in the present specification should be understood as follows.

The word " first, "" second," and the like, used to distinguish one element from another, are to be understood to include plural representations unless the context clearly dictates otherwise. The scope of the right should not be limited by these terms.

It should be understood that the terms "comprises" or "having" does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

It should be understood that the term "at least one" includes all possible combinations from one or more related items. For example, the meaning of "at least one of the first item, the second item and the third item" means not only the first item, the second item or the third item, but also the second item and the second item among the first item, Means any combination of items that can be presented from more than one.

Hereinafter, preferred embodiments of a method of driving an organic light emitting display according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 4 is a schematic view of an organic light emitting display device according to an embodiment of the present invention, and FIG. 5 is a circuit diagram illustrating a data driver and pixel structure of an OLED display device according to an embodiment of the present invention.

Referring to FIGS. 4 and 5, an organic light emitting display device according to an embodiment of the present invention includes a display panel 100 and a panel driver.

The display panel 100 includes a plurality of gate lines GL, a plurality of data lines DL, a plurality of driving power lines PL, a plurality of reference voltage lines RL, and a plurality of pixels P .

Each of the plurality of pixels P is formed in a pixel region defined in the display panel 100. The plurality of pixels P include an organic light emitting diode OLED and a pixel circuit for driving the organic light emitting diode OLED. .

The differential voltage Vdata-Vref between the data voltage Vdata and the reference voltage Vref is charged to the capacitor Cst connected between the gate electrode and the source electrode of the driving TFT DT to which the first driving power supply VDD is supplied And emits the organic light emitting diode OLED with the data current Ioled flowing from the first driving power supply VDD to the second driving power supply VSS through the driving TFT DT according to the charging voltage of the capacitor Cst .

Each of the plurality of pixels P 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 be composed of adjacent red pixels, green pixels, and blue pixels, or may be composed of adjacent red pixels, green pixels, blue pixels, and white pixels.

And the plurality of gate lines GL may be formed in parallel in the first direction (e.g., the horizontal direction) in the display panel 100. At this time, a scan signal (scan, gate drive signal) is applied to the gate line GL from the gate driver 300 of the panel driver.

The plurality of data lines DL may be formed in a second direction (e.g., a vertical direction) so as to intersect with the plurality of gate lines GL. At this time, the data voltage Vdata is supplied from the data driver 200 of the panel driver to the data line DL. The data voltage Vdata has a voltage level to which a compensation voltage corresponding to the shift of the threshold voltage Vth of the driving TFT DT of the pixel P is added and the compensation voltage will be described later.

The plurality of reference voltage lines RL are formed in parallel with the plurality of data lines DL. The display reference voltage Vref or the precharging voltage Vpre may be selectively supplied from the data driver 200 to the reference voltage line RL. At this time, the display reference voltage Vref is supplied to each reference voltage line RL during the data charging period of each pixel P.

The plurality of driving power supply lines PL may be formed in parallel with the gate lines GL and supply the first driving power VDD to the pixels P. [

5, each of the plurality of pixels P charges the capacitor Cst with a difference voltage Vdata-Vref between the data voltage Vdata and the reference voltage Vref during a data charging period, And a pixel circuit PC for supplying the data current Ioled to the organic light emitting diode OLED according to the charging voltage of the capacitor Cst during the light emission period.

The pixel circuit PC of each pixel P is configured to include a switching TFT ST1, a driving TFT DT, and a capacitor Cst.

Here, the TFTs ST1 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 TFT. However, the present invention is not limited thereto, and the TFTs ST1 and DT may be formed of a P-type TFT.

The switching TFT ST1 has a gate electrode connected to the gate line GL, a source electrode (first electrode) connected to the data line DL and a first node n1 connected to the gate electrode of the driving TFT DT. (Second electrode) connected to the drain electrode.

The switching TFT ST1 is turned on in response to a scan signal having a gate-on voltage level supplied to the gate line GL to turn on the data voltage Vdata supplied to the data line DL To the gate electrode of one node n1, that is, the driving TFT DT.

The capacitor Cst is connected between the gate electrode and the drain electrode of the driving TFT DT, that is, between the first node n1 and the second node n2. The capacitor Cst charges the difference voltage between the voltages supplied to the first node n1 and the second node n2, and then switches the driving TFT DT according to the charged voltage.

The driving TFT DT includes a gate electrode commonly connected to the drain electrode of the switching TFT (ST1) and the first electrode of the capacitor (Cst). The driving TFT DT includes a source electrode connected to the driving power supply line PL. The driving TFT DT includes a drain electrode of the second switching TFT ST2, a second electrode of the capacitor Cst, and a drain electrode commonly connected to an anode of the organic light emitting diode OLED .

The driving TFT DT controls the amount of current flowing to the organic light emitting diode OLED by the first driving power supply VDD by being turned on by the voltage of the capacitor Cst every light emitting period.

The organic light emitting diode OLED emits monochromatic light having a luminance corresponding to the data current Ioled by the data current Ioled supplied from the pixel circuit PC, i.e., the driving TFT DT.

The organic light emitting diode OLED includes an anode electrode (not shown) connected to the second node n2 of the pixel circuit PC, an organic layer (not shown) formed on the anode electrode, and an organic layer And a cathode electrode (not shown) to which the second driving power supply VSS is supplied.

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. At this time, the second driving power source VSS may be supplied to the cathode electrode of the organic light emitting diode OLED through a second driving power line (not shown) formed in a line shape.

The panel driver includes a data driver 200, a gate driver 300, a timing controller 400, a memory 500 storing deterioration prediction model data, and a deterioration prediction unit 600 for generating deterioration prediction data ).

The deterioration predictor 600 according to the embodiment of the present invention can be applied without limitation to the structure of the pixel circuit for driving the organic light emitting diode OLED. The pixel structure described with reference to FIG. 5 describes one of various embodiments applicable to the present invention.

Here, the deterioration prediction model data stored in the memory 500 is generated by grasping deterioration characteristics of the organic light emitting diode OLED according to luminance with time and input data through driving experiments of the display panel in advance, This is a result obtained by sampling a plurality of display panels over a long period of time.

Therefore, in the present invention, it is assumed that the deterioration predictive model data stored in the memory 500 is reliable, and the deterioration of the organic light emitting diode OLED according to the driving time and the input data is predicted based on the deterioration prediction model data do.

The gate driver 300 is connected to a plurality of gate lines GL and operates according to the mode control of the timing controller 400.

The gate driver 300 generates a scan signal (scan) having a gate-on voltage level for each horizontal period according to a gate control signal GCS supplied from the timing controller 400. And sequentially supplies the generated scan signal (scan) to the plurality of gate lines GL.

The scan signal (scan) has a gate-on voltage level during a data charging period of each pixel P and has a gate-off voltage level during a light-emitting period of each pixel P. The gate driver 300 may be a shift register that sequentially outputs a scan signal (scan).

The gate driver 300 may be formed in the form of an integrated circuit (IC), or integrated with a substrate of the display panel 100 together with a transistor forming process of each pixel P.

The gate driver 300 is connected to each of a plurality of driving power lines PL1 to PLm and supplies driving power VDD supplied from an external power supply unit to a plurality of driving power lines PL1 to PLm do.

The timing controller 400 operates the data driver 200 and the gate driver 300 based on the timing synchronization signal TSS.

The timing synchronization signal TSS may be a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable DE, a clock DCLK, or the like. The gate control signal GCS may include a gate start signal and a plurality of clock signals. The data control signal DCS may be a data start signal, a data shift signal, a data output signal, or the like.

The timing controller 400 corrects input data (Idata) input from the outside based on the deterioration predictive data provided from the deterioration predictor 600, and generates corrected pixel data. Thereafter, the pixel data (DATA) corrected by the deterioration prediction method is supplied to the data driver (200).

The pixel data DATA to be supplied to each pixel P has a voltage level at which a compensation voltage for compensating the threshold voltage / mobility of the driving transistor DT of each pixel P is reflected.

The input data Idata may be input data of red, green, and blue to be supplied to one unit pixel. When the unit pixel is composed of a red pixel, a green pixel, and a blue pixel, one pixel data (DATA) may be red, green, or blue data.

On the other hand, when the unit pixel is composed of a red pixel, a green pixel, a blue pixel and a white pixel, one pixel data (DATA) may be data of red, green, blue or white.

The data driver 200 is connected to the plurality of data lines D1 to Dn and operates according to the mode control of the timing controller 400. [ A data charging period for charging each pixel with a data voltage and a light emitting period for emitting an organic light emitting diode (OLED).

The data driver 200 includes a data voltage generating unit 210 and a switching unit 240.

The data voltage generator 210 converts the input pixel data DATA into a data voltage Vdata and supplies the data voltage to the data line DL. To this end, the data voltage generator 210 includes a shift register for generating a sampling signal, a latch for latching pixel data (DATA) according to a sampling signal, a plurality of gradation voltages using a plurality of reference gamma voltages A digital-to-analog converter (DAC) for selecting and outputting a gradation voltage corresponding to pixel data (DATA) latched in a plurality of gradation voltages as a data voltage (Vdata) And an output unit for outputting the output signal.

The switching unit 240 includes a plurality of first switches 240a and a plurality of second switches 240b.

The plurality of first switches 240a switches the data voltage Vdata or the precharging voltage Vpre_d to supply the data voltage to the data line DL in the driving mode. The plurality of second switches 240b switches the display reference voltage Vref or the precharging voltage Vpre and supplies the switching voltage to the reference voltage line RL.

FIG. 6 is a diagram illustrating a deterioration predictor according to an embodiment of the present invention, and FIG. 7 is a diagram illustrating the error corrector shown in FIG.

6 and 7, the degradation predicting unit 600 according to an embodiment of the present invention continuously accumulates stress data according to image data, The degree of deterioration of the organic light emitting diode (OLED) is predicted.

To this end, the degradation predicting unit 600 according to the embodiment of the present invention includes an error correction unit 610, an averaging filter 620, and a memory 630.

Here, the error correction unit 610 includes a frame counter 612, a bit counter 614, and an error correction unit 616. The averaging filter 620 includes a bit reduction unit 622 and a bit expansion unit 624.

 The frame counter 612 of the error correction unit 610 is a counter that increments by one at every frame or at a specific frame interval. The frame counter 612 counts every frame or a predetermined number of frames, And provides it to the error compensator 616. [

The bit counter 614 counts the maximum number of valid bits of the frame count value input from the frame counter 612.

For example, when the frame count value is a decimal number 12, converting it to a binary number results in 1100, and the maximum number of bits of the frame count value 12 is 4 at this time. That is, four bits are used to indicate the frame count value 12.

As another example, when the frame count value is a decimal number 16, it is converted to binary number 10000, and the maximum number of bits of the frame count value 16 is 5 at this time. That is, five bits are used to indicate the frame count value 16.

As described above, if the frame counter value of the frame counter 612 is 16 to 31, the output value of the bit counter 614 is 5. If the frame count value is 32 to 63, the output value of the bit counter 614 is 6 . If the frame counter value is 32 to 63, the output value of the bit counter 614 is 6. If the frame counter value is 64 to 127, the bit counter is 7.

Since the error compensator 616 approximates the output value n of the frame counter for real-time calculation, an error may exist. Therefore, a correction bit is added to calculate the average value of the more accurate stress data.

The error compensator 616 outputs 1 or 0 as the frame counter 612 outputs the error correction bits using the output value. When correcting the bit, 1 is outputted as the error correction bit value, and when the bit is not corrected, the error correction bit is outputted as 0.

The average stress data up to the present is accumulated and stored in the memory 630. When the current frame is the nth frame, average stress data up to the (n-1) th frame is provided to the average filter 620. [

The averaging filter 620 reduces or expands the frame count value and the number of bits provided by the error correction unit 610 and outputs the average count value to the organic light emitting diode (OLED) based on the average stress data up to the n- OLED) and outputs the calculated average stress value.

Subsequently, the bit reduction unit 622 of the averaging filter 620 performs a division operation. The number of bits input from the error correction unit 610 is right-bit-shifted to generate a sub- Reduce the bit. That is, when 7 bits are input, the number is reduced to 6 bits. When 5 bits are inputted, the number of bits is reduced to 4 bits to reduce the number of bits.

The bit expander 624 of the average filter 620 multiplies the number of bits input from the error corrector 610 by a left bit shift and outputs the lower bits of the number of input bits . That is, when 7 bits are input, the number of bits is increased to 8 bits. When 5 bits are inputted, the number of bits is increased to 6 bits to expand the number of bits.

The average value of the stress data is calculated through the Average filter 620 as shown in Equation (1) below.

[Equation 1]

In Equation (1),? Is a value corresponding to 1 / n and has a value between 0 and 1. If the number of frames is small and the value of α is large, the average value may be greatly affected by the current input value. In contrast, as the number of frames is large and the value of alpha is small, the previous average value may be influenced by the current input value.

That is, as the frame number increases with time, the input value does not significantly affect the change of the average value even if the input value is significantly different from the previous average value.

Such an operation is necessarily difficult to implement in real time hardware because it includes division operation. Therefore, there are restrictions when applied to a display device.

However, if the value of the number of frames (n) is composed of X power of 2 (multiplication factor), an approximate expression is applied to shift the bits by the X, and the operation of 1 / n can be simply performed. However, when the value of n is not a power of 2, an error may be caused to a large extent by applying an approximation formula.

The degradation predicting unit 600 according to the embodiment of the present invention performs a division and a multiplication operation using a bit shift operation and calculates a mean filtering value of the stress data by a simple operation, that is, a compensation value of the OLED The average stress data based on the degradation prediction data is generated.

Here, as described above, since an error may occur in the result value when the number of frames does not correspond to the square of 2, an error correction bit is added to reduce an operation error according to the bit shift operation .

FIG. 8 is a view for explaining an example in which an error occurs in a bit shift operation, and FIG. 9 is a diagram for explaining a method of correcting an error by a bit shift operation.

Referring to FIGS. 8 and 9, when only a bit shift operation is performed, an error may occur in an operation due to a large influence on an average value before a current input value.

Therefore, an error correction bit is added to reduce the shift periodically, that is, to reduce the value of n, thereby adjusting the current input value to a large extent.

For example, when a 5-bit right shift operation is performed, the input value is reflected more than the average value through the 4-bit shift operation rather than the 5-bit shift in the section where the error appears, have.

Specifically, the frame number 17 is 5 bits when converted into a binary number, but is closer to 17 than 32, which is represented by 5 bits. Therefore, the shift operation is performed to 4 bits in this case.

Likewise, the frame number 33 should be 6 bits, but it is closer to 32, which is represented by 5 bits than 64, which is expressed by 6 bits. In this case, the shift operation is performed to 5 bits.

In the present invention, when the frame number n is sufficiently large, the average value of the stress data according to the image data can be calculated only by the bit shift operation. Based on the average value of the calculated stress data, the degradation prediction of the organic light emitting diode Data can be generated.

10 is a diagram for explaining the effect of increasing the accuracy of the degradation prediction data by applying the degradation prediction unit according to the embodiment of the present invention.

Referring to FIG. 10, it is possible to increase the accuracy of the degradation prediction data through the degradation prediction unit described above, and to perform accurate degradation prediction even with a small memory use. In addition, it is possible to prevent image quality deterioration due to the duration of the driving time, and to reduce the size of the memory, thereby preventing an increase in manufacturing cost due to application of the degradation prediction compensation method.

It will be understood by those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

100: display panel 200: data driver
300: Gate driver 400: Timing controller
500: memory 600: deterioration prediction unit
610: Error correction unit 620: Averaging filter
630: Memory

Claims (9)

1. A display device comprising: a display panel including a plurality of pixels each comprising an organic light emitting diode and a pixel circuit for emitting the organic light emitting diode;
A gate driver for supplying a scan signal and a drive voltage for driving the plurality of pixels;
A data driver for supplying a data voltage and a reference voltage to the plurality of pixels during driving driving;
A timing controller for controlling the gate driver and the data driver to operate;
A memory in which degradation prediction model data is stored; And
And a deterioration predictor for filtering the stress average data and performing a bit shift operation to generate average stress data of a current frame. The method according to claim 1,
Wherein the degradation prediction unit comprises:
An error correction unit for converting the frame count value into a bit value by approximating and generating a correction bit for correcting an error caused by the approximation of the frame count value; And
A bit reduction unit for reducing the lower bits of the number of input bits by right bit shift of the number of input bits and a left bit shift of the number of input bits to increase the lower bits of the number of input bits And a bit expanding unit for expanding the organic EL display device. 3. The method of claim 2,
The above-
Frame count value and the number of bits, and calculates an average stress value for compensation of the organic light emitting diode based on the average stress data up to the (n-1) th frame. The method according to claim 1,
Wherein when the number of frames does not correspond to a square of 2, an error correction bit is added to reduce an operation error due to a bit shift operation. 5. The method of claim 4,
wherein an n-1 bit shift operation is applied in an interval in which an error occurs when an n-bit write shift operation is performed. A method of driving an organic light emitting display device including a display panel including a plurality of pixels constituted by a pixel circuit for emitting an organic light emitting diode and a driving circuit for driving the display panel,
filtering average stress data according to image data of n frames and performing bit shift operation to generate average stress data of a current frame;
Converting the frame count value into a bit value by approximating the frame count value, and generating a correction bit for correcting an error caused by the approximation of the frame count value;
The number of input bits is shifted by a right bit to reduce the lower bits of the number of input bits or the number of input bits is left bit shifted to increase the lower bits of the number of input bits step; And
And compensating deterioration of the organic light emitting diode formed on the plurality of pixels by using an average stress value obtained by performing a bit shift operation. The method according to claim 6,
The frame count value and the number of bits are reduced or expanded,
and calculating an average stress value for compensation of the organic light emitting diode based on average stress data up to the (n-1) th frame. 8. The method of claim 7,
Wherein when the number of frames does not correspond to a square of 2, an error correction bit is added to reduce an operation error due to a bit shift operation. 9. The method of claim 8,
wherein when an n-bit write shift operation is performed, an n-1 bit shift operation is applied in an interval where a large amount of error is present.

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