KR102268522B1 - Organic light emitting diode display device and method for driving the same - Google Patents

Abstract

The present invention relates to an OLED display device and a driving method for preventing overcompensation by sensing moisture permeation, and the driving method of the OLED display device according to the present invention includes: detecting a short circuit of a pixel when power is turned off by a user; when it is determined that the pixel is not shorted, performing RTDS and RS and then turning off the power; And when it is determined that the pixel is shorted, the step of turning off the power without performing the RTDS and RS is provided.

Description

OLED display device and driving method {Organic light emitting diode display device and method for driving the same}

The present invention relates to an OLED display device and a driving method, and to an OLED display device and a driving method for preventing overcompensation by sensing moisture permeation.

Recently, as a flat panel display device that displays an image using digital data, a liquid crystal display (LCD) using liquid crystal and an OLED display using an organic light emitting diode (OLED) are representative. .

Among them, OLED display is a self-luminous device that emits light from an organic light emitting layer by recombination of electrons and holes. It has high luminance, low driving voltage, and is expected to be a next-generation display device because it can be thinned.

Each of the plurality of pixels constituting the OLED display device includes an OLED element composed of an organic light emitting layer between an anode and a cathode, and a pixel circuit independently driving the OLED element. The pixel circuit includes a switching thin film transistor (TFT) that supplies a data voltage to the storage capacitor, and a driving TFT that controls the driving current according to the driving voltage charged in the storage capacitor and supplies it to the OLED device, The device generates light proportional to the driving current.

The OLED display device has a problem of luminance non-uniformity due to variations in driving characteristics (threshold voltage, mobility) of the driving TFT between pixels due to process variations and changes over time. In order to solve this problem, the OLED display uses an external compensation method of sensing the driving characteristics of each pixel and compensating for data to be supplied to each pixel using the sensing value.

In the OLED display device, the method and period of sensing the threshold voltage change amount of the driving TFT and the mobility change amount of the driving TFT are different in the conventional image quality compensation technology.

The sensing method for extracting the change in the threshold voltage (Vth) of the driving TFT operates the driving TFT in a source follower method so that the gate-source voltage (Vgs) of the driving TFT is in a saturation state. After reaching (that is, when the drain-source current of the driving TFT becomes zero), the amount of change in the threshold voltage of the driving TFT is detected based on the source voltage of the driving TFT. An offset value for data compensation is obtained according to the detected threshold voltage change amount of the driving TFT.

In addition, the sensing method for extracting the change in mobility (μ) of the driving TFT is a constant voltage higher than the threshold voltage of the driving TFT at the gate of the driving TFT in order to define current capability characteristics excluding the threshold voltage (Vth) of the driving TFT. (Vdata+X, where X is a voltage according to offset value compensation) is applied to turn on the driving TFT, and in this state, the source voltage (Vs) of the driving TFT charged for a certain time is set to the gain value for data compensation. saved Since this sensing method is performed in a state in which the driving TFT is turned on, the time required for sensing is short and the sensing speed is fast.

The sensing method for extracting the change in the threshold voltage (Vth) of the driving TFT requires a sufficient sensing period because the sensing speed is slow. Therefore, in response to the power-off command signal from the user, the image display is finished until the driving power is turned off. On the other hand, in the sensing method for sensing the mobility of the driving TFT, since the sensing speed is fast, after the driving power is turned on in response to a power-on command signal from the user, before image display, or within the image display driving period It may be performed in vertical blank periods.

However, since the OLED display device may be exposed to moisture or the like during use, a short may occur between signal lines due to moisture permeation. As such, when a short occurs between signal lines due to moisture permeation, an error occurs in a sensing method for extracting a change in the threshold voltage (Vth) of the driving TFT, and there is a possibility that an error may occur in data compensation due to the sensing error. .

The present invention has been devised to solve such a problem, and it is an object of the present invention to provide an OLED display device and a driving method that can prevent a sensing error and data compensation error due to moisture permeation by recognizing a short circuit between signal lines in advance. There is this.

In an OLED display device according to the present invention for achieving the above object, a plurality of pixel regions are defined by a plurality of data lines, scan lines, and sensing voltage read-out lines, and each pixel includes an OLED and a driving TFT. OLED panel having; A timing controller that outputs a control signal (EVSS PMOS_Control, EVSS NMOS Control) for sensing a threshold voltage of the driving TFT when the power is turned off by a user; and a short circuit of each pixel is detected and, when the short circuit is detected, a threshold of the driving TFT It is characterized by having an SD processing unit that prevents voltage sensing from being performed.

Here, the SD processing unit includes: a first comparator for outputting a logic value by comparing the short sensing voltage with a maximum reference voltage; a second comparator for outputting a logic value by comparing the short sensing voltage with the minimum reference voltage; An AND gate that outputs a control signal by performing an AND operation on the logic values output from the first and second comparators, and is turned on/off according to the control signal output from the AND gate to generate the control signal EVSS PMOS_Control It is characterized in that it is provided with a switch for blocking or passing.

The SD processing unit is connected in series with a first comparator that compares the short sensing voltage and the maximum reference voltage to output a logic value, and a second comparator that compares the short sensing voltage and the minimum reference voltage and outputs a logic value, and and first and second switches respectively turned on/off according to the logic values output from the first and second comparators to cut off or pass the control signal EVSS PMOS_Control.

In addition, a method of driving an OLED display device according to the present invention for achieving the above object includes: detecting a short circuit of a pixel when power is turned off by a user; when it is determined that the pixel is not shorted, performing RTDS and RS and then turning off the power; And when it is determined that the pixel is shorted, the step of turning off the power without performing the RTDS and RS is characterized.

Here, the detecting of the short circuit of the pixel includes precharging the sensing voltage readout line with an initialization voltage, applying a data voltage to the data voltage supply line, and receiving a short voltage from the sensing voltage readout line. reading, comparing the short voltage with a reference voltage and determining that the pixel is not shorted if the short voltage is within the reference voltage range, and determining that the pixel is shorted if the short voltage is outside the reference voltage range It is characterized in that it includes a step.

The OLED display and driving method according to the present invention having the above characteristics have the following effects.

That is, when it is determined that the driving circuit of each pixel is shorted in the panel of the OLED display device due to moisture permeation, the power is turned off without performing RTDS and RS, thereby preventing sensing errors and data compensation errors due to moisture permeation.

1 is a block diagram of an organic light emitting diode display including an image quality compensation device according to an embodiment of the present invention;
2 is a diagram illustrating a detailed configuration of an external compensation pixel and a connection configuration between a timing controller and a data driving circuit according to the present invention;
3A is a detailed configuration diagram of a first embodiment of the SD processing unit of FIG. 2;
3B is a detailed configuration diagram of a second embodiment of the SD processing unit of FIG.
4 is an operation flowchart for explaining a method of driving an OLED display device according to the present invention;
5 is a timing diagram of each signal pulse applied when sensing a threshold voltage (Vth) for external compensation of FIG. 2 ;

An OLED display device and a driving method according to the present invention having the above characteristics will be described in more detail with reference to the accompanying drawings.

First, in the method of driving an OLED display device according to the present invention, when a user turns on power, the OLED display device is driven to display an input image signal. And, when the user turns off the power, the short detection sensing (SDS) is performed before RTDS (Real Time Driver Sensing) and RS (Real Time S mode Sensing) are performed.

That is, conventionally, when the user turns off the power, RTDS and RS are performed.

However, in the present invention, when the user turns off the power, sensing (Short Detect Sensing; SDS) is performed to detect a short in the driving circuit due to moisture permeation before proceeding with RTDS and RS, and when a short is detected, RTDS And without RS, moisture is removed through AGP (Auto Generating Pattern) and the power is turned off. If a short is not detected in the above, RTDS and RS are performed and the power is turned off.

Specific methods for the RTDS, RS and SDS will be described later.

1 is a block diagram of an organic light emitting display device including an image quality compensation device according to an embodiment of the present invention.

An organic light emitting diode display according to an exemplary embodiment includes a display panel 10 , a data driving circuit 12 , a gate driving circuit 13 , a timing controller 11 , and a memory 20 .

A plurality of data lines 14 and a plurality of gate lines 15 cross each other in the display panel 10 , and pixels are arranged in a matrix form in each crossed area. The plurality (m) of the data lines 14 and the plurality of (n) gate lines 15, as well as the plurality (m) of sensing voltage readout lines and a power generator ( A plurality of (m) power supply lines for receiving the high potential driving voltage EVDD and the low potential driving voltage EVSS from (not shown in the drawing) are provided.

The data driving circuit 12 supplies the sensing data voltage synchronized to the sensing first gate pulse to the pixels based on the data control signal DDC from the timing controller 11 during sensing driving. , The sensing voltages input from the display panel 10 through the sensing voltage readout lines are converted into digital values and supplied to the timing controller 11 . The data driving circuit 12 converts the digital compensation data MDATA input from the timing controller 11 to a data voltage for image display based on the data control signal DDC during image display driving, and then converts the image The data voltage for display is supplied to the data voltage supply lines 14 in synchronization with the first gate pulse for image display.

The gate driving circuit 13 generates a gate pulse based on a gate control signal GDC from the timing controller 11 .

The timing controller 11 is configured to operate the data driving circuit 12 based on timing signals such as a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a dot clock signal DCLK, and a data enable signal DE. A data control signal DDC for controlling the operation timing of , and a gate control signal GDC for controlling the operation timing of the gate driving circuit 13 are generated. In addition, the timing controller 11 modulates the input digital video data DATA with reference to the digital sensing voltage value supplied from the data driving circuit 12, thereby compensating for changes in threshold voltage and mobility of the driving TFT. After generating the digital compensation data MDATA, the digital compensation data MDATA is supplied to the data driving circuit 12 .

The timing controller 11 controls operation timings of the data driving circuit 12 and the gate driving circuit 13 during sensing driving, and controls the digital sensing voltage Vsen input from the data driving circuit 12 . Based on this, the threshold voltage change amount and mobility change amount of the driving TFT are found. The timing controller 11 determines an offset value for compensating for a change in threshold voltage of the driving TFT and a gain value for compensating for a change in mobility of the driving TFT, and then inputs the gain and offset values to digital video data (DATA) is applied to generate digital compensation data MDATA to be applied to the pixel.

The memory 20 may store a reference voltage, an offset value, and a reference compensation value as a reference for determining a gain value, which are standards for deriving a mobility change amount.

2 is a detailed configuration diagram of a pixel for external compensation and a connection configuration between a timing controller and a data driving circuit according to the present invention, FIG. 3A is a detailed configuration diagram of the first embodiment of the SD processing unit of FIG. 2 , and FIG. 3B is FIG. 2 It is a detailed configuration diagram of the second embodiment of the SD processing unit of

Referring to FIG. 2 , each pixel P includes an OLED, a driving TFT DT, a storage capacitor Cst, a first switch TFT ST1 , and a second switch TFT ST2 .

The OLED includes an anode electrode connected to the second node N2, a cathode electrode connected to an input terminal of the low potential driving voltage EVSS, and an organic compound layer positioned between the anode electrode and the cathode electrode.

The driving TFT DT controls the current Ioled flowing through the OLED according to the gate-source voltage Vgs. The driving TFT DT includes a gate electrode connected to a first node N1 , a drain electrode connected to an input terminal of the high potential driving voltage EVDD, and a source electrode connected to the second node N2 .

The storage capacitor Cst is connected between the first node N1 and the second node N2 .

The first switch TFT ST1 receives the sensing data voltage (a constant voltage higher than the threshold voltage of the driving TFT) charged in the data voltage supply line 14A in response to the sensing first gate pulse SCAN during sensing driving. It is applied to the first node N1. The first switch TFT ST1 is a data voltage Vdata for image display charged in the data voltage supply line 14A in response to a first gate pulse SCAN for image display when driving an image display, and a threshold voltage change of the driving TFT and a data voltage for which the change in mobility is compensated) is applied to the first node N1 to turn on the driving TFT. The first switch TFT ST1 has a gate electrode connected to the first gate line 15A, a drain electrode connected to the data voltage supply line 14 , and a source electrode connected to the first node N1 . .

The second switch TFT ST2 switches the current flow between the second node N2 and the sensing voltage read-out line 14B in response to the second gate pulse SEN for sensing during sensing driving, so that the second node ( The source voltage of N2) is stored in the sensing capacitor Cx of the sensing voltage readout line 14B. The second switch TFT ST2 switches the current flow between the second node N2 and the sensing voltage readout line 14B in response to the second gate pulse SEN for image display when driving the image display, so that the driving TFT The source voltage of (DT) is reset to the initialization voltage (Vpre). A gate electrode of the second switch TFT ST2 is connected to a second gate line 15B, a drain electrode of the second switch TFT ST2 is connected to a second node N2, and the second switch TFT The source electrode of ST2 is connected to the sensing voltage readout line 14B.

The data driving circuit 12 is connected to the pixel P through a data voltage supply line 14A and a sensing voltage read-out line 14B. A sensing capacitor Cx for storing the source voltage of the second node N2 as the sensing voltage Vsen is formed in the sensing voltage readout line 14B. The data driving circuit 12 includes a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), an initialization switch (SW1), and a sampling switch (SW2).

The digital-to-analog converter (DAC) generates a sensing data voltage Vdata under the control of the timing controller 11 during sensing driving and outputs it to the data voltage supply line 14A. The digital-to-analog converter (DAC) converts digital compensation data into a data voltage (Vdata) for image display under the control of the timing controller 11 during image display driving, and outputs the converted digital compensation data to the data voltage supply line 14A.

The initialization switch SW1 switches a current flow between the initialization voltage Vpre input terminal and the sensing voltage readout line 14B in response to the initialization control signal SPRE.

The sampling switch SW2 switches the current flow between the sensing voltage readout line 14B and the analog-to-digital converter ADC in response to the sampling control signal SSAM during sensing driving, and the sensing voltage for a predetermined time. The source voltage of the driving TFT DT stored in the sensing capacitor Cx of the readout line 14B is supplied as a sensing voltage to the analog-to-digital converter ADC. The analog-to-digital converter ADC converts the analog sensing voltage stored in the sensing capacitor Cx into a digital value Vsen and supplies it to the timing controller 11 . The sampling switch SW2 continuously maintains a turned-off state in response to the sampling control signal SSAM when an image display is driven.

In addition, a circuit for proceeding off RTDS and RS is configured on the control PCB (C-PCB).

That is, when the user turns off the power in the timing controller 11 , the control signals EVSS PMOS_Control and NMOS_Control for controlling the off RTDS and RS are output. The control signal EVSS PMOS_Control and the control signal EVSS NMOS_Control have the same phase.

Accordingly, in order to detect a short circuit of the driving circuit of each pixel due to moisture permeation in the control PCB (C-PCB), the short sensing voltage Vshort and the reference voltages Vref_Max and Vref_Min are compared to determine whether the driving circuit is shorted. An SD processing unit that passes or blocks a control signal (EVSS PMOS_Control), and a control signal (EVSS NMOS Control) for controlling the OFF RTDS and RS are turned on/off according to a low potential driving voltage at the cathode terminal of the OLED It is turned on/off according to the third switch ST3 for applying EVSS and the control signal EVSS PMOS_Control passed from the SD processing unit to provide a power supply voltage (eg, 6 to 6.5V) to the cathode terminal of the OLED. ) for applying the fourth switch ST4 is configured.

Here, the SD processing unit is configured as shown in FIG. 3A or 3B.

That is, as shown in FIG. 3A , the SD processing unit includes a first comparator OP1 that compares the short sensing voltage Vshort and the maximum reference voltage Vref-Max and outputs a logic value, and the short sensing voltage Vshort. A second comparator OP2 comparing the minimum reference voltage Vref-Min and outputting a logical value, and controlling the logical values output from the first and second comparators OP1 and OP2 by AND operation The AND gate AND outputting a signal and the AND gate AND are turned on/off according to the control signal output from the AND gate and output the control signal EVSS PMOS_Control to the gate terminal of the fourth switch ST4 It may be configured by providing a fifth switch (S3).

In addition, as shown in FIG. 3B , the SD processing unit includes a first comparator OP1 that compares the short sensing voltage Vshort with the maximum reference voltage Vref-Max and outputs a logic value, and the short sensing voltage A second comparator OP2 that compares (Vshort) and the minimum reference voltage (Vref-Min) to output a logic value, and a second comparator OP2 connected in series with each other and the logic value output from the first and second comparators OP1 and OP2 The fifth and sixth switches S3 and S4 that are turned on/off accordingly and output the control signal EVSS PMOS_Control to the gate terminal of the fourth switch ST4 may be provided.

The driving method of the OLED display device according to the present invention configured as described above will be described as follows.

4 is an operation flowchart for explaining a method of driving an OLED display device according to the present invention.

A driving method will be described in conjunction with FIGS. 2 and 4 as follows.

When the power is turned on by the user (S1), the timing controller 11 outputs the control signals (EVSS PMOS_Control, EVSS NMOS Control) for controlling the off RTDS and RS as a logic high (H) signal. The third switch ST3 is turned on and the fourth switch ST4 is turned off so that the low potential driving voltage EVSS is applied to the cathode terminal of the OLED of the pixel P. Then, the OLED display is driven to display an image using the input data signal (S2).

When the user turns off the power while the image is being displayed as described above (S3), the timing controller 11 logically outputs control signals (EVSS PMOS_Control, EVSS NMOS Control) for controlling the off RTDS and RS. A low value (L) signal is output, and a short circuit of the pixel driving circuit P is detected (S4).

In the method for detecting the short circuit, a first gate pulse Scan is applied as a low signal and an initialization control signal SPRE is applied at a high level to turn on the initialization switch SW1 to turn on the sensing voltage readout line. After pre-charging 14B to the initialization voltage Vpre, the initialization control signal SPRE is applied at a low level.

Then, a voltage of a data voltage (about 4.5V) is applied to the data voltage supply line 14A, and a sampling control signal SSAM is applied at a high level, and a voltage Vshort from the sensing voltage readout line 14B is applied. ) is read.

Here, when the driving circuit of the pixel is not shorted, the voltage Vshort read from the sensing voltage readout line 14B will be the precharged initialization voltage Vpre. However, when the driving circuit of the pixel is short-circuited, the voltage Vshort read from the sensing voltage readout line 14B will be different from the precharged initialization voltage Vpre.

Accordingly, the SD processing unit compares the voltage Vshort with the maximum value Vref_Max of the reference voltage and the minimum value Vref_Min of the reference voltage so that the voltage Vshort is lower than the maximum value Vref_Max of the reference voltage and the reference voltage If it is higher than the minimum value Vref_Min of the pixel, it is determined that the driving circuit of the pixel is not shorted. If the voltage Vshort is higher than the maximum value Vref_Max of the reference voltage or is lower than the minimum value Vref_Min of the reference voltage, it is determined that the pixel is not shorted. It is determined that the driving circuit of the is shorted (S5).

Here, when it is determined that the driving circuit of the pixel is not shorted ( S5 ), the SD processing unit applies the control signal EVSS PMOS_Control, which is a logic low (L) signal, to the fourth switch ST4 .

As such, when the control signals EVSS PMOS_Control and EVSS NMOS_Control are output to a low logic value, the third switch ST3 is turned off, and the fourth switch ST4 is turned on to turn on the power supply voltage (6 to 6.5V). ) is applied to the cathode terminal of the OLED.

Then, in this state, RTDS (Real Time Driver Sensing) and RS (Real Time S mode Sensing) are performed (S7).

Here, the reason for applying the power supply voltage (6 ~ 6.5V) to the cathode terminal of the OLED in the above is as follows.

When sensing the threshold voltage of the driving TFT (DT), which will be described below, when the sensing data voltage Vdata is higher than the threshold voltage of the OLED, the current flows through the OLED, so that the accurate sensing of the threshold voltage of the OLED is not performed. Accordingly, in order to prevent this, when the threshold voltage of the driving TFT DT is sensed, a power supply voltage (6 to 6.5V) is applied to the cathode terminal of the OLED to reverse bias.

5 is a timing diagram of each signal pulse applied when sensing the threshold voltage (Vth) for external compensation of FIG. 2 .

In general, an OLED display device is driven by a plurality of data drive ICs, and each data drive IC also has different output offsets. Therefore, in order to match the output offset characteristics of each data drive IC, the voltage output from the display panel to the timing controller 11 through the analog-to-digital converter (ADC) is sensed from the display panel (Panel) to compensate for the driving deviation, and each data driver Compensate for the output offset of the IC. This process is called RTDS (Real Time Driver Sensing).

In addition, as described above, in order to solve the luminance non-uniformity problem due to the deviation of the driving characteristics (threshold voltage, mobility) of the driving TFT between pixels, the threshold of the driving TFT is sensed and data to be supplied to each pixel using the sensing value is should be compensated This process of sensing the threshold of the driving TFT is referred to as RS (Real Time S mode Sensing).

The operation of the pixel P during sensing driving will be described in conjunction with FIGS. 2 and 5 .

When a high-level first gate pulse Scan for sensing and an initialization control signal SPRE are applied to an arbitrary pixel P, the first switch TFT ST1 is turned on, and the data voltage supply line ( A sensing data voltage Vdata is applied to the gate electrode of the driving TFT DT from the digital-analog converter DAC of the data driving circuit 12 through 14A). In addition, the initialization switch SW1 is turned on by the initialization control signal SPRE to pre-charge the sensing voltage readout line 14B to the initialization voltage Vpre of a predetermined level. Here, the initialization voltage Vpre may be a predetermined reference voltage level that is the sensing data voltage Vdata.

Next, the initialization switch SW1 is turned off by applying the initialization control signal SPRE to a low level, and a second gate pulse SEN for sensing of a high level is applied to the second switch TFT SW2. turns on.

Accordingly, the driving TFT (DT) is driven in the saturation region according to the difference voltage between the sensing data voltage (Vdata, reference voltage) stored in the storage capacitor (Cst) and the initialization voltage (Vpre), so that the sink current flows, The initialization voltage Vpre of the sensing voltage readout line 14B rises to a voltage corresponding to a saturation region.

After that, when the voltage corresponding to the saturation region reaches the threshold voltage Vth of the driving TFT DT, the sensing voltage readout line 14B is in a saturated state, and the capacitor Cx is in a saturated state. voltage is stored.

And when the saturation state is reached, when the second gate pulse Sense for sensing is applied at a low level and the sampling control signal SSAM is applied at a high level, the sampling switch SW2 is turned on. The threshold voltage of the driving TFT DT is sensed by sampling the voltage Vsen charged in the capacitor Cx by the analog-to-digital converter ADC.

When the compensation value for compensating for the threshold voltage change and the mobility change of the driving TFT is determined through the sensing driving, the input data voltage is compensated with the compensation value, and the compensated data voltage is applied to the pixels during the image display driving. to display the image.

As described above, when the RTDS and RS processes are completed, the power of the display device is cut off (S8).

Meanwhile, if it is determined in step S5 that the driving circuit of the pixel is not shorted, the SD processing unit applies the control signal EVSS PMOS_Control, which is a logic low (L) signal, to the fourth switch ST4. to remove moisture from the panel by driving the AGP (Auto Generate Pattern) for a certain period of time (S6), and cut off the power of the display device without proceeding with the RTDS and RS (S8).

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is common in the technical field to which the present invention pertains that various substitutions, modifications and changes are possible without departing from the technical spirit of the present invention. It will be clear to those who have the knowledge of

10: display panel 11: timing controller
12: data driving circuit 13: gate driving circuit
20: memory

Claims (5)

A plurality of pixel regions are defined by a plurality of data lines, scan lines, and sensing voltage read-out lines, and each pixel includes an OLED panel having an OLED and a driving TFT;
a timing controller outputting a control signal (EVSS PMOS_Control, EVSS NMOS Control) for sensing a threshold voltage of the driving TFT of each pixel of the OLED panel when power is turned off by a user;
an SD processing unit that detects a short circuit in each pixel of the OLED panel and passes or blocks the control signal EVSS PMOS_Control output from the timing controller according to the presence or absence of the short circuit;
a first switching unit turned on/off according to the control signal (EVSS NMOS Control) output from the timing controller to apply a low potential driving voltage (EVSS) to the cathode terminal of the OLED; And
and a second switching unit that is turned on/off according to the control signal EVSS PMOS_Control passed from the SD processing unit to apply a power voltage to the cathode terminal of the OLED. The method of claim 1,
The SD processing unit,
a first comparator for outputting a logic value by comparing the short sensing voltage with the maximum reference voltage;
a second comparator comparing the short sensing voltage with a minimum reference voltage and outputting a logic value;
an AND gate for outputting a control signal by performing an AND operation on the logic values output from the first and second comparators;
and a switch that is turned on/off according to a control signal output from the AND gate to block or pass the control signal EVSS PMOS_Control. The method of claim 1,
The SD processing unit,
a first comparator for outputting a logic value by comparing the short sensing voltage with the maximum reference voltage;
a second comparator comparing the short sensing voltage with a minimum reference voltage and outputting a logic value;
1 . An OLED display device comprising: first and second switches connected in series to each other and turned on/off according to logic values output from the first and second comparators to block or pass the control signal EVSS PMOS_Control. A method of driving an OLED display device in which a plurality of pixel regions are defined by a plurality of data voltage supply lines, scan lines, and sensing voltage read-out lines, each pixel having an OLED and a driving TFT, the method comprising:
detecting a short circuit of a pixel when power is turned off by a user;
when it is determined that the pixel is not shorted, performing Real Time Driver Sensing (RTDS) and Real Time S mode Sensing (RS) and then turning off the power; And
When it is determined that the pixel is shorted, the method of driving an OLED display device comprising the step of turning off the power without performing the RTDS and RS. 5. The method of claim 4,
Detecting the short of the pixel includes
precharging the sensing voltage readout line to an initialization voltage;
applying a data voltage to the data voltage supply line and reading a short voltage from the sensing voltage readout line;
Comparing the short voltage with a reference voltage, determining that the pixel is not shorted if the short voltage is within the range of the reference voltage, and determining that the pixel is shorted if the short voltage is outside the range of the reference voltage A method of driving an OLED display device.

Images