KR100602356B1 - Light emitting display and driving method thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting display device and a driving method thereof capable of minimizing image unevenness due to variations in characteristics of transistors.

A light emitting display device according to the present invention includes a plurality of pixels defined by a plurality of scan lines supplied with a scan signal, a plurality of data lines supplied with a data signal, and a plurality of power supply lines, wherein each pixel is a sub-pixel. And a pixel circuit for outputting a current corresponding to the data signal from the power supply line supplied with power corresponding to the frame, and a light emitting element for emitting light by the current output from the pixel circuit.

According to this configuration, the present invention can display an image of a desired gray scale by supplying power having different levels to the anode electrode of the organic light emitting element according to the digital data signal for each sub-frame, Image unevenness can be minimized.

Description

LIGHT EMITTING DISPLAY AND DRIVING METHOD THEREOF             

1 is a circuit diagram illustrating a pixel of a general light emitting display device.

2 is a diagram illustrating a light emitting display device according to a first embodiment of the present invention.

3 is a diagram illustrating the first power supply unit illustrated in FIG. 2.

4 is a circuit diagram illustrating a pixel illustrated in FIG. 2.

5 is a waveform diagram illustrating a method of driving a light emitting display device according to a first embodiment of the present invention.

6 is a diagram illustrating a pixel of a light emitting display device according to a second embodiment of the present invention.

7 is a waveform diagram illustrating a method of driving a light emitting display device according to a second embodiment of the present invention.

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

11, 111: pixel 40, 140: pixel circuit

110: display unit 120: scan driver

130: data driver 150: first power supply

152: shift register section 154: voltage generating section

156: selection unit 170: second power supply unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting display device, and more particularly, to a light emitting display device and a driving method thereof capable of minimizing image unevenness due to variations in transistor characteristics.

Recently, various flat panel displays have been developed to reduce weight and volume, which are disadvantages of cathode ray tubes. The flat panel display includes a liquid crystal display, a field emission display, a plasma display panel, a light emitting display, and the like.

Among the flat panel displays, a light emitting display device is a self-light emitting device that emits a fluorescent material by recombination of electrons and holes, and includes an inorganic light emitting display device including an inorganic light emitting layer and an organic light emitting layer according to materials and structures. It is roughly divided into. In this case, the organic light emitting diode display may be referred to as an electroluminescent display.

Such a light emitting display device has an advantage of having a fast response speed, such as a cathode ray tube, compared to a passive light emitting device requiring a separate light source like a liquid crystal display device.

1 is a circuit diagram illustrating a pixel of a general light emitting display device.

Referring to FIG. 1, each pixel 11 of a typical light emitting display device is disposed to be adjacent to an intersection region of the scan line Sn and the data line Dm. Each pixel 11 is selected when a scan signal is applied to the scan line Sn, and generates light corresponding to the data signal supplied to the data line Dm.

To this end, each pixel 11 includes a first power source VDD, a second power source VSS, a light emitting element OLED, and a pixel circuit 40.

The anode electrode of the light emitting element OLED is connected to the pixel circuit 40, and the cathode electrode is connected to the second power source VSS. In this case, the light emitting device OLED may be an organic light emitting device.

The organic light emitting diode includes an emission layer (EML), an electron transport layer (ETL), and a hole transport layer (HTL) of an organic material formed between the anode electrode and the cathode electrode. The organic light emitting diode may further include an electron injection layer (EIL) and a hole injection layer (HIL). In the organic light emitting diode, when a voltage is applied between the anode electrode and the cathode electrode, electrons generated from the cathode electrode move toward the light emitting layer through the electron injection layer and the electron transport layer, and holes generated from the anode electrode are transferred to the hole injection layer and the hole transport layer. It moves to the light emitting layer through. Accordingly, in the light emitting layer, light is generated by collision between electrons and holes supplied from the electron transporting layer and the hole transporting layer and recombination.

The pixel circuit 40 includes first and second transistors M1 and M2 and a capacitor C. Here, the second transistor M2 and the first transistor M1 are P-type metal oxide semiconductor field effect transistors (MOSFETs). The second power source VSS may have a voltage level lower than that of the first power source VDD and may have a ground voltage level.

The gate electrode of the first transistor M1 is connected to the scan line Sn, the source electrode is connected to the data line Dm, and the drain electrode is connected to the first node N1. The first transistor M1 supplies the data signal from the data line Dm to the first node N1 in response to the scan signal supplied to the scan line Sn.

The capacitor C stores the voltage corresponding to the data signal supplied on the first node N1 via the first transistor M1 in the period in which the scan signal is supplied to the scan line Sn, and then the first transistor. When M1 is off, the on state of the second transistor M2 is maintained for one frame.

The gate electrode of the second transistor M2 is connected to the first node N1 to which the drain electrode and the capacitor C of the first transistor M1 are commonly connected, and the source electrode is connected to the first power source VDD. In addition, the drain electrode is connected to the anode electrode of the light emitting element OLED. The second transistor M2 adjusts the amount of current corresponding to the data signal supplied from the first power supply VDD to the light emitting element OLED according to the data signal. Accordingly, the light emitting device OLED emits light by the current supplied from the first power supply VDD via the second transistor M2.

The driving of the pixels 11 as described above is as follows. First, the first transistor M1 is turned on in a section in which a scan signal in a low state is supplied to the scan line Sn. Therefore, the data signal supplied to the data line Dm is supplied to the gate electrode of the second transistor M2 via the first transistor M1 and the first node N1. In this case, the capacitor C stores the difference voltage between the gate electrode of the second transistor M2 and the first power supply VDD.

Accordingly, the second transistor M2 is turned on according to the voltage of the first node N1 to supply a current corresponding to the data signal to the light emitting device OLED. Accordingly, the light emitting element OLED emits light by the current supplied from the second transistor M2 to display an image.

Then, in the period in which the scan signal in the HIGH state is supplied to the scan line Sn, the on state of the second transistor M2 is maintained by the voltage corresponding to the data signal stored in the capacitor C, so that the light emitting device ( OLED) emits light for one frame period to display an image.

Such a general light emitting display device further includes a compensation circuit for compensating for the variation of the threshold voltage Vth of the second transistor M2 by the manufacturing process. Accordingly, although the light emitting display device having the compensation circuit adopts the offset compensation method or the current program method, this also has a limitation in displaying a uniform image.

Accordingly, it is an object of the present invention to provide a light emitting display device and a method of driving the same, which can minimize image irregularities caused by variations in characteristics of transistors.

As a means for achieving the above object, a first aspect of the present invention includes a plurality of pixels defined by a plurality of scan lines supplied with a scan signal, a plurality of data lines supplied with a data signal, and a plurality of power lines; And each pixel includes a pixel circuit for outputting a current corresponding to the data signal from the power line to which power is supplied corresponding to each sub-frame, and a light emitting element for emitting light by a current output from the pixel circuit. A light emitting display device is provided.

Preferably, each pixel displays a desired gray scale by the sum of the brightness of the light emitting element for each sub-frame. Also, the data signal is a digital data signal having i (where i is a positive integer) bit corresponding to the sub-frame. The level of the power source is increased as the most significant bit of the digital data signal.

A second aspect of the present invention is defined by a plurality of scan lines, a plurality of data lines and a plurality of first power lines, and receives a current corresponding to a data signal supplied to the data line from the first power line to emit light. An image display unit including a plurality of pixels, a scan driver for supplying a scan signal to the scan lines, a data driver for supplying the data signal to the data lines, and a subframe corresponding to each sub-frame of one frame. A light emitting display device including a first power supply unit for supplying power to the first power line is provided.

A third aspect of the present invention provides a method of driving a light emitting display device including a plurality of pixels defined by a plurality of scan lines, a plurality of data lines, and a plurality of power lines, the method comprising: supplying a scan signal to the scan lines And supplying a data signal to the data lines, supplying a power corresponding to each sub-frame of one frame to the power lines, and supplying a current corresponding to the data signal from the power supply to each pixel. A method of driving a light emitting display device, the method comprising: supplying light to each pixel by supplying the same.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 2 to 7 which can be easily implemented by those skilled in the art.

2 is a diagram illustrating a light emitting display device according to a first embodiment of the present invention.

Referring to FIG. 2, the light emitting display device according to the first embodiment of the present invention includes an image display unit 110, a scan driver 120, a data driver 130, a first power supply unit 150, and a second unit. The power supply unit 170 is provided.

The image display unit 110 includes a plurality of pixels 111 defined by a plurality of scan lines S1 to SN, a plurality of data lines D1 to DM, and a plurality of pixel power lines V1 to VN. At this time, the pixel power lines V1 to VN are arranged to be parallel to the scan lines S1 to SN formed on the image display unit 110.

Each pixel 111 is selected when a scan signal is applied to the scan lines S1 to SN, and receives a current corresponding to a data signal supplied to the data lines D1 to DM from the power lines V1 to VN. Will generate light. Specifically, each of the pixels 111 receives a current corresponding to each bit of the digital data signal from the first power source having different levels supplied to the power lines V1 to VN to emit light of the light emitting device OLED which emits light. By adjusting and displaying the gray scale, a desired image is displayed.

The scan driver 120 generates scan signals for sequentially driving the scan lines S1 to SN in response to scan control signals from a controller (not shown), that is, a start pulse and a clock signal, thereby scanning the scan lines S1 to SN. ) Sequentially.

The data driver 130 transmits an i-bit (where i is a positive integer) digital data signal from the controller to each pixel 111 through the data lines D1 to DM in response to data control signals supplied from the controller. Supply. That is, the data driver 130 supplies each bit digital data signal of the i bit digital data signal to the data lines D1 to DM for each j sub-frames (where j is a positive integer equal to or greater than i). . At this time, the least significant bit of the i-bit digital data signal is supplied to the first sub-frame.

The second power supply unit 170 generates a second power different from the first power and supplies the same to the cathode electrode of each pixel 111. At this time, the cathode electrode of each pixel 111 is formed on the front surface of the image display unit 110.

The first power supply 150 generates the first power of different levels for each of the j sub-frames constituting one frame. The first power supply unit 150 sequentially supplies driving power to the power lines V1 through VN in synchronization with the scan signals supplied to the scan lines S1 through SN according to each bit of the i-bit digital data signal. . At this time, the driving power has a higher level toward an upper bit of the i-bit digital data signal.

3 is a block diagram illustrating the frequency supply unit 150 illustrated in FIG. 2.

Referring to FIG. 3 and FIG. 2, the frequency supply unit 150 of the light emitting display device includes a voltage generator 154, a shift register unit 152, and a selection unit 156.

The voltage generator 154 generates the first power VO having different levels and supplies it to the selector 156.

The shift register unit 152 includes a plurality of shift registers. Each shift register sequentially shifts the voltage selection start signal VSSS supplied in synchronization with the scan signal and supplies it to the selection unit 156. That is, each shift register generates a voltage selection signal that is sequentially shifted and supplies it to the selection unit 156. At this time, each shift register sequentially shifts k bits to generate a voltage selection signal and supply the voltage selection signal to the selection unit 156. Here, when the i-bit digital data signal is 8 bits and is composed of eight sub-frames, each shift register generates a 3-bit voltage selection signal and supplies it to the selection unit 156.

The selector 156 includes a plurality of voltage selectors. At this time, each voltage selector may be an analog switch. Each voltage selector selects one of a plurality of different first power sources VO supplied from the voltage generator 154 according to a voltage selection signal supplied from each shift register, and selects one of the plurality of first power lines V1 to VN. Supply sequentially. At this time, the first power supplied sequentially from the selector 156 to the first power lines V1 to VN is supplied in synchronization with the scan signals supplied to the scan lines S1 to SN.

4 is a circuit diagram illustrating a pixel illustrated in FIG. 2.

Referring to FIG. 4 and FIG. 2, each pixel 111 includes a light emitting element OLED and a pixel circuit 140.

The anode electrode of the light emitting device OLED is connected to the pixel circuit 140, and the cathode electrode is connected to the second power line to which the second power source VSS is supplied. In this case, the light emitting device OLED may be an organic light emitting device. The organic light emitting diode includes an emission layer (EML), an electron transport layer (ETL), and a hole transport layer (HTL) of an organic material formed between the anode electrode and the cathode electrode. The organic light emitting diode may further include an electron injection layer (EIL) and a hole injection layer (HIL). In the organic light emitting diode, when a voltage is applied between the anode electrode and the cathode electrode, electrons generated from the cathode electrode move toward the light emitting layer through the electron injection layer and the electron transport layer, and holes generated from the anode electrode are transferred to the hole injection layer and the hole transport layer. It moves to the light emitting layer through. Accordingly, in the light emitting layer, light is generated by collision between electrons and holes supplied from the electron transporting layer and the hole transporting layer and recombination.

The pixel circuit 140 includes a first transistor M1, a second transistor M2, and a capacitor C. The first and second transistors M1 and M2 are P-type metal oxide semiconductor field effect transistors (MOSFETs). On the other hand, when the pixel circuit 140 is formed of a P-type transistor, the second power supply VSS may have a voltage level lower than that of the first power supply supplied to the first power supply line Vn, and may have a ground voltage level.

The gate electrode of the first transistor M1 is connected to the scan line Sn, the source electrode is connected to the data line Dm, and the drain electrode is connected to the first node N1. The first transistor M1 supplies the digital data signal from the data line Dm to the first node N1 in response to the scan signal supplied to the scan line Sn.

The gate electrode of the second transistor M2 is connected to the first node N1 to which the drain electrode and the capacitor C of the first transistor M1 are commonly connected, and the source electrode is connected to the first power line Vn. The drain electrode is connected to the anode electrode of the light emitting element OLED. The second transistor M2 adjusts the amount of current supplied from the first power line Vn to the light emitting device OLED according to the voltage supplied from the capacitor C to its gate electrode.

The first electrode of the capacitor C is electrically connected to the first node N1, that is, the gate electrode of the second transistor M2, and the second electrode is electrically connected to the first power supply line Vn. The capacitor C stores a voltage corresponding to the digital data signal supplied on the first node N1 via the first transistor M1 in a section in which the scan signal is supplied to the scan line Sn. When the first transistor M1 is turned off, the second transistor M2 is kept in the on state for each sub-frame constituting one frame.

Accordingly, the light emitting device OLED emits light by the current supplied from the first power line Vn through the second transistor M2.

5 is a waveform diagram illustrating a method of driving a light emitting display device according to a first embodiment of the present invention.

Referring to FIG. 5 and FIG. 4, the light emitting display device and the driving method thereof according to the first embodiment of the present invention display brightness of the light emitting device OLED in order to display a desired gray scale by adjusting the brightness of the light emitting device OLED. In order to display a desired gray scale by adjusting the, one frame is divided into a plurality of sub-frames SF1 to SFj corresponding to each bit of the i-bit digital data signal and having the same emission period. In this case, the first to j th sub-frames SF1 to SFj have gray levels corresponding to the brightnesses of different weights, and the ratio of the gray levels corresponding to the brightness of the first to j sub-frames SF1 to SFj is 2 ⁰ : 2 ¹ : 2 ² : 2 ³ : 2 ⁴ : 2 ⁵ : ...: 2 ⁱ

The light emitting display device and the driving method thereof according to the first embodiment of the present invention will be described below.

First, in the first sub-frame SF1 of one frame, scan signals SS1 to SSn in a low state are sequentially supplied to the scan lines S1 to SN, and at the same time, the first power lines V1 to VN. ) Is supplied with a first power source VDD1 of a first level. Accordingly, the first bit digital data signal of the i bits supplied to the data lines D1 to DM is sequentially turned on by the first transistor M1 connected to each of the scan lines S1 to SN sequentially turned on. It is supplied to the gate electrode of each second transistor M2 via the transistor M1 and the first node N1. At this time, each capacitor C stores the difference voltage between the first bit digital data signal of the first node N1 and the first power source VDD1 of the first level.

Then, the scan signals SS1 to SSn having a high state are supplied to the scan lines S1 to SN, so that a voltage corresponding to the first bit digital data signal stored in each capacitor C is applied to each second transistor ( Supplied to the gate terminal of M2). Accordingly, the second transistor M2 receives a current corresponding to the first bit digital data signal from the first power lines V1 to VN to which the first power source VDD1 of the first level is supplied. To be supplied.

Accordingly, each of the light emitting devices OLED receives a current corresponding to the voltage stored in the capacitor C from the first power supply VDD1 of the first level supplied to the first power supply lines V1 through VN during the first sub-frame. Supplied with "0" and "2 ⁰ " The light is emitted at a brightness corresponding to one of the gray levels. That is, the light emitting element OLED has "2 ⁰ " when the first bit digital data signal is " ⁰ ". When light is emitted at a brightness corresponding to the gradation and is "1", the light is not emitted.

Further, in the second sub-frame SF2 of one frame, scan signals SS1 to SSn in a low state are sequentially supplied to the scan lines S1 to SN, and to the power lines V1 to VN. The second power supply VDD2 of the second level higher than the first power supply VDD1 of the first level is supplied. Accordingly, the second bit digital data signal among the i bits supplied to the data lines D1 to DM by being sequentially turned on by the first transistor M1 connected to each of the scan lines S1 to SN may be converted into a first first bit. It is supplied to the gate electrode of each second transistor M2 via the transistor M1 and the first node N1. At this time, each capacitor C stores the difference voltage between the second bit digital data signal of the first node N1 and the second power source VDD2 of the second level.

Then, the scan signals SS1 to SSn having a high state are supplied to the scan lines S1 to SN, so that a voltage corresponding to the second bit digital data signal stored in each capacitor C is applied to each second transistor ( Supplied to the gate terminal of M2). Accordingly, the second transistor M2 supplies the current corresponding to the second bit digital data signal to each light emitting device OLED from the power lines V1 to VN to which the second power source VDD2 of the second level is supplied. Done.

Therefore, during the second sub-frame, each light emitting device OLED receives a current corresponding to the voltage stored in the capacitor C from the second power source VDD2 of the second level supplied to the first power source lines V1 through VN. Supplied with "0" and "2 ¹ " The light is emitted at a brightness corresponding to one of the gray levels. That is, the light emitting device OLED is " 2 ¹ " when the second bit digital data signal is " 0 &quot;. When light is emitted at a brightness corresponding to the gradation and is "1", the light is not emitted.

Similarly, in the third sub-frame SF3 of one frame, the light emitting device OLED is higher than the second power source VDD2 of the second level supplied to the first power source lines V1 to VN in the same manner as described above. &Quot; 0 " and " 2 ² " received from the third power supply VDD3 of the third level corresponding to the third bit digital data signal. The light is emitted at a brightness corresponding to one of the gray levels. That is, the light emitting device OLED is " 2 ² " when the third bit digital data signal is " 0 &quot;. When light is emitted at a brightness corresponding to the gradation and is "1", the light is not emitted.

Similarly, in each of the fourth to jth sub-frames SF4 to SFj of one frame, the light emitting elements OLED are supplied to the first power lines V1 to VN in the same manner as described above. The current corresponding to the fourth to i-th bit digital data signals is supplied from the first power sources VDD4 to VDDj having the j-th level to emit light with brightness corresponding to "0" or "2 ³ to 2 ⁱ " gray scale.

As described above, in the light emitting display device and the driving method thereof, the level of the first power supplies VDD1 to VDDj supplied to the anode electrodes of the light emitting diode OLED is set to the sub-frames SF1 to SFj. By differentiating for each), an image having a desired gradation can be displayed by the sum of the brightness for each sub-frame SF1 to SFj. That is, the first embodiment of the present invention provides the first power sources VDD1 to VDDj having different levels so as to correspond to the respective bits of the i-bit digital data signal during each sub-frame SF1 to SFj having the same emission period. By supplying to the first power lines V1 to VN, an image of a desired gradation can be displayed.

Accordingly, the first embodiment of the present invention can minimize the image irregularity caused by the variation of the characteristics of the transistor. Further, according to the first embodiment of the present invention, the gray scale expression time of each sub-frame SF1 to SFj can be sufficiently secured by equalizing the light emission period of each sub-frame SF1 to SFj.

6 is a diagram illustrating a pixel of a light emitting display device according to a second embodiment of the present invention, and FIG. 7 is a waveform diagram illustrating a method of driving the light emitting display device according to the second embodiment of the present invention.

6 and 7, the pixel of the light emitting display device according to the second exemplary embodiment of the present invention is described with reference to FIG. 4 except for the conduction type of the transistors M1 and M2 constituting the pixel circuit 140. Same as the first embodiment of the present invention shown.

That is, the light emitting display device according to the second embodiment of the present invention is the same as the first embodiment of the present invention except for the scan signal for driving the N-type transistors M1 and M2. Accordingly, those skilled in the art will be able to easily implement the second embodiment of the present invention only by the above description of the first embodiment of the present invention. Therefore, the light emitting display device and the driving method thereof according to the second embodiment of the present invention will be replaced with the description of the first embodiment of the present invention including the P-type transistor.

On the other hand, in the light emitting display device and the driving method thereof according to the embodiment of the present invention, each pixel 111 is not limited to having the two transistors M1 and M2 and one capacitor C described above. It may be composed of at least two transistors and at least one capacitor.

In addition, in the light emitting display device and the driving method thereof, each sub-frame has been described as having the same light emitting period, but may have different light emitting periods for gray scale expression and image quality improvement.

The light emitting display device and the driving method thereof according to the embodiment of the present invention can be equally applied to a display device for displaying an image by controlling a current.

The above detailed description and drawings are merely exemplary of the present invention, which are used only for the purpose of illustrating the present invention and are not intended to limit the scope of the present invention as defined in the claims or the claims. Accordingly, those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical protection scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

As described above, the light emitting display device and the driving method thereof according to the exemplary embodiment of the present invention provide a desired gray level by supplying a first power source having a different level to the anode electrode of the organic light emitting diode according to the digital data signal for each sub-frame. Can display an image.

Accordingly, the present invention can minimize the image non-uniformity caused by the variation of the characteristics of the transistor. In addition, the present invention can sufficiently secure the gray scale expression time of each sub-frame by making the light emission period of each sub-frame the same.

Claims (22)

A plurality of pixels defined by a plurality of scan lines supplied with a scan signal, a plurality of data lines supplied with a data signal, and a plurality of power supply lines, Each pixel, A pixel circuit for outputting a current corresponding to the data signal from the power supply line to which power corresponding to each sub-frame is supplied; And a light emitting element emitting light by current output from the pixel circuit. The method of claim 1, Wherein each pixel displays a desired gray scale by the sum of brightnesses of the light emitting elements for each sub-frame. The method of claim 2, And the data signal is a digital data signal having i (where i is a positive integer) bit corresponding to the sub-frame. The method of claim 3, wherein And the level of the power is increased to the most significant bit of the digital data signal. The method of claim 3, wherein And the power is supplied to the power line in synchronization with a scan signal supplied to the scan line. The method of claim 1, And the power supply line is parallel to the scan line. The method of claim 1, The pixel circuit, A first transistor controlled by a scan signal supplied to the scan line and outputting the data signal supplied to the data line; A second transistor for supplying the current from the power supply line to the light emitting device according to its gate-source voltage; And a capacitor configured to store a data signal from the first transistor and adjust a voltage between a gate and a source of the second transistor according to the stored data signal. An image including a plurality of pixels defined by a plurality of scan lines, a plurality of data lines, and a plurality of first power lines, and configured to emit light by receiving a current corresponding to a data signal supplied to the data line from the first power line. With display part, A scan driver for supplying scan signals to the scan lines; A data driver for supplying the data signal to the data line; And a first power supply for supplying first power corresponding to each sub-frame of one frame to the first power line. The method of claim 8, Wherein each pixel displays a desired gray scale by the sum of brightnesses emitted for each sub-frame. The method of claim 8, And the data signal is a digital data signal having i (where i is a positive integer) bit corresponding to the sub-frame. The method of claim 10, And the level of the first power supply is increased toward the most significant bit of the digital data signal. The method of claim 8, And the first power source is supplied to the first power line so as to be synchronized with the scan signal. The method of claim 8, The first power line is parallel to the scan line. The method of claim 8, The first power supply unit, A voltage generator for generating different voltages, A shift register unit generating a voltage selection signal corresponding to each sub-frame; And a selector configured to select one of the different voltages supplied from the voltage generator and supply the selected voltage to the first power line according to the voltage selection signal. The method of claim 8, And a second power supply for supplying a second power different from the first power to a second power line connected to each of the pixels. The method of claim 15, Each pixel, A pixel circuit for outputting a current corresponding to the data signal from the first power supply line; And a light emitting element positioned between the pixel circuit and the second power supply line and emitting light by a current supplied from the pixel circuit. The method of claim 16, The pixel circuit, A first transistor controlled by a scan signal supplied to the scan line and outputting the data signal supplied to the data line; A second transistor for supplying the current from the first power supply line to the light emitting device according to a voltage between its gate and source; And a capacitor configured to store a data signal from the first transistor and adjust a voltage between a gate and a source of the second transistor according to the stored data signal. A driving method of a light emitting display device including a plurality of pixels defined by a plurality of scan lines, a plurality of data lines, and a plurality of power lines, Supplying a scan signal to the scan lines; Supplying a data signal to the data lines; Supplying power lines corresponding to each sub-frame of one frame to the power lines; And supplying a current corresponding to the data signal from the power source to each of the pixels to emit light of each of the pixels. The method of claim 18, And each pixel displays a desired gray scale by a sum of brightnesses emitted for each sub-frame. The method of claim 19, And the data signal is a digital data signal having i (where i is a positive integer) bit corresponding to the sub-frame. The method of claim 20, And the level of the power is increased to the most significant bit of the digital data signal. The method of claim 18, And the power is supplied to the power line in synchronization with the scan signal.

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