KR20130002115A - Driving circuit for organic light emitting diode display and method for driving the same - Google Patents

Abstract

PURPOSE: A driving circuit of an organic electroluminescent display device and a driving method are provided to minimize short-term afterimages generated in a panel driving process by compensating a threshold voltage and mobility of a driving transistor. CONSTITUTION: A first transistor(T21) outputs a data signal according to a gate signal. A second transistor(T22) outputs a reference voltage according to the gate signal. A third transistor(T23) outputs a power voltage. A first capacitor(C21) stores the data signal. A fourth transistor(T24) provides current to drive an organic electroluminescent display device. A second capacitor(C22) provides a constant bias voltage to the gate of the fourth transistor.

Description

Driving circuit and method for driving an organic light emitting display device {Driving circuit for organic light emitting diode display and method for driving the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving circuit and a driving method of an organic light emitting display device, and more particularly, to compensate for a threshold voltage and mobility of a driving transistor to compensate for short-term afterimages and luminance unevenness generated during panel driving. The present invention relates to a driving circuit and a driving method of an organic light emitting display device capable of minimizing the number.

It is expected that the 21st century will be an information society, and accordingly, it is important to develop a high performance flat panel display device for multimedia because it is necessary to easily obtain information from anywhere. In particular, technology development related to device development of semiconductors and display devices in relation to communication and computers is becoming important, and one of the devices that are attracting attention as a color display device is an organic light emitting diode (OLED).

Organic light emitting devices can be classified into passive matrix organic light emitting devices (PMOLEDs) and active matrix organic light emitting devices (AMOLEDs) according to their structure. As is required, the development of AMOLED is essential.

Each of the pixels constituting the organic light emitting display device includes a pixel composed of an organic light emitting layer between an anode and a cathode and a pixel circuit driving each pixel independently. The pixel circuit mainly includes a switching transistor and a capacitor and a driving transistor. The switching transistor charges the data signal to the capacitor in response to the scan pulse, and the driving transistor adjusts the gray level of the pixel by adjusting the amount of current supplied to the pixel according to the magnitude of the data voltage charged in the capacitor.

However, when a characteristic difference such as a threshold voltage and mobility occurs between driving transistors formed in each pixel, a change occurs in the amount of current driving the organic light emitting diode OLED. The luminance difference occurs between them. In general, the difference in characteristics of the driving transistors causes stains or patterns on the screen, and the difference in characteristics between the driving transistors generated while driving the liquid crystal panel may cause short-term and long-term afterimages in the liquid crystal panel. In addition, a deviation may occur between pixels due to a resistance of a power supply voltage line to which a power supply voltage is applied when driving the liquid crystal panel, which may cause uneven brightness of the liquid crystal panel.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problem. In providing.

Other objects and features of the present invention will be described in the following description of the invention and claims.

In order to achieve the above object, the driving circuit of the organic light emitting display device according to an embodiment of the present invention, the driving circuit of the organic light emitting display device for controlling the current supplied to the organic light emitting display device, the gate is A first transistor is connected to a gate line to which a gate signal is applied, and a source is connected to a data line to which a data signal is applied. The first transistor outputs the data signal according to the gate signal, and a gate is connected to the gate line. A second transistor for outputting the reference voltage according to the gate signal, a gate connected to a control line to which a control signal is applied, and a source to a power supply line to which a source voltage is applied A third transistor connected to the third transistor for outputting the power supply voltage according to the control signal, and one end of the first transistor A first capacitor for storing the data signal, a gate connected to a drain of the second transistor, and a source connected to a drain of the third transistor, the other end of the third transistor being connected to a drain of the third transistor; A fourth transistor connected to the fourth transistor for providing a current for driving the organic light emitting diode, one end of which is connected to a drain of the third transistor, and the other end of which is connected to a drain of the second transistor, and a gate of the fourth transistor The second capacitor and the anode for providing a constant bias voltage to the drain of the fourth transistor, the cathode includes an organic light emitting device connected to the ground voltage line to which the ground voltage is applied.

A data voltage is applied to the source of the first transistor, a reference voltage is applied to the source of the second transistor, and a power supply voltage is applied to the source of the third transistor.

When the gate-on signal is applied to the gates of the first and second transistors, and the control-on signal is applied to the gates of the third transistors to turn on the first to third transistors, the drain voltage of the third transistors is turned on. Is higher than the drain voltage of the second transistor.

The gate-on signal is applied to the gates of the first and second transistors, and the control-off signal is applied to the gates of the third transistor so that the first and second transistors are turned on and the third transistor is turned off. In this case, the drain voltage of the third transistor is set to a value obtained by adding a threshold voltage of the fourth transistor to a reference voltage.

A gate is connected to the gate line, a source is connected to the reference voltage line, a drain is connected to a drain of the fourth transistor, and includes a fifth transistor that suppresses initial emission of the organic light emitting diode.

A gate-off signal is applied to the gates of the first and second transistors, a control-on signal is applied to the gates of the third transistor, and the first and second transistors are turned off, and the third transistor is turned on. In this case, a current for driving the organic light emitting device flows through the second transistor, the fourth transistor, and the fifth transistor to the reference voltage line.

The potential of the reference voltage line and the potential of the ground voltage line connected to the cathode of the organic light emitting diode are maintained at the same potential.

The fourth transistor is a source follower.

The first to fourth transistors are formed of any one selected from a P-type transistor, an N-type transistor, amorphous silicon (a-Si), and an oxide.

The reference voltage is a ground voltage.

In addition, a method of driving an organic light emitting display device according to an embodiment of the present invention includes a plurality of control lines, a plurality of reference voltage lines, a plurality of gate lines, a plurality of data lines formed to cross the plurality of gate lines, The organic light emitting display device includes a plurality of pixels formed in a region where the plurality of gate lines and the plurality of data lines cross each other and including a driving transistor for supplying current to each organic light emitting diode. The method of claim 1, wherein a plurality of control lines and a plurality of gate lines apply a control on signal and a gate on signal, respectively, to initialize data voltages and bias voltages in first and second capacitors connected to the driving transistor. A control off signal is applied to a control line of the A threshold voltage compensation step of setting a voltage to a value obtained by adding a threshold voltage of the driving transistor; a data writing step of distributing the data voltage applied through the plurality of data lines by the first and second capacitors; And applying a control on signal and a gate off signal to the control line and the plurality of gate lines, respectively, to turn on the driving transistor to supply current to the organic light emitting diode.

The bias voltage is a voltage applied to the reference voltage line.

In the initializing step, a path of a current supplied to the organic light emitting diode is changed to the reference voltage line to suppress initial light emission of the organic light emitting diode.

The potential of the reference voltage line and the potential of the ground voltage line connected to the cathode of the organic light emitting diode are maintained at the same potential.

The drive transistor is a source follower.

The driving transistor is formed of any one selected from a P-type transistor, an N-type transistor, amorphous silicon (a-Si), and an oxide.

As described above, the driving circuit and the driving method of the organic light emitting display device according to the present invention compensate for the threshold voltage and mobility of the driving transistor to provide an effect of minimizing short-term afterimage and luminance unevenness generated during panel driving. do.

1 is a view illustrating a driving circuit of an organic light emitting display device according to an embodiment of the present invention.
2 is a timing diagram of a driving circuit of an organic light emitting display device according to an embodiment of the present invention;
3 illustrates a driving circuit of an organic light emitting display device according to another exemplary embodiment of the present invention.
4 is a timing diagram of a driving circuit of an organic light emitting display device according to another embodiment of the present invention;
5 is a diagram illustrating a driving circuit of an organic light emitting display device according to still another embodiment of the present invention;

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

1 is a diagram illustrating a driving circuit of an organic light emitting display device according to an embodiment of the present invention.

Referring to FIG. 1, M × N unit pixels are defined on an array substrate, and each unit pixel is arranged in a matrix form.

Each unit pixel 110 includes a first transistor T11 to a fourth transistor T14, first and second capacitors C11 and C12, and an organic light emitting diode OLED11.

The gate of the first transistor T11 is connected to the gate line GL, the source is connected to the data line DL, the drain is connected to the first node N11, and outputs a data signal according to the gate signal. .

The gate of the second transistor T12 is connected to the control line CL, the source is connected to the power supply voltage line VDD, the drain is connected to the second node N12, and the power supply voltage is output in accordance with the control signal. do.

The gate of the third transistor T13 is connected to the first node N11, the source is connected to the second node N12, the drain is connected to the third node N13, and the organic light emitting diode OLED11 is connected. Provide a current to drive it.

A gate of the fourth transistor T14 is connected to the gate line GL, a source is connected to the third node N13, and a drain is connected to the reference voltage line VREF. In this case, for example, the ground voltage GND may be applied to the reference voltage line VREF.

In addition, one end of the first capacitor C11 is connected to the first node N11 and the other end is connected to the reference voltage terminal 16. One end of the second capacitor C12 is connected to the first node N11 and the other end is connected to the second node N12.

The anode of the organic light emitting diode OLED11 is connected to the third node N13 and the cathode is connected to the ground voltage GND.

Although the first to fourth transistors T11 to T14 have been described using P-type transistors as an example, the first to fourth transistors T11 to T14 may be formed of N-type transistors, amorphous silicon (a-Si), oxides, and the like.

1 and 2, driving of an organic light emitting display device according to an exemplary embodiment will be described. 2 is a timing diagram of a driving circuit of an organic light emitting display device according to an embodiment of the present invention.

1 and 2, an organic light emitting display device according to an embodiment of the present invention includes an initialization section A, a data writing section B, and a light emitting section C during one frame.

First, when, for example, a low level signal is applied to the control line CL and the gate line GL during the initialization period A, the second transistor T12 connected to the control line CL is turned on. The first transistor T11 connected to the gate line GL is turned on and the voltage of the second node N12 is a value obtained by subtracting the threshold voltage Vth of the second transistor T12 from the power supply voltage VDD. It is initialized.

Then, for example, when the high level signal is applied to the control line CL and the low level signal is applied to the gate line GL during the data write period B, the first signal connected to the control line CL is applied. The two transistors T12 are turned off and the first transistor T11 connected to the gate line GL is continuously turned on.

At this time, the third transistor T13 is turned on by the voltage stored in the first capacitor C11 so that the voltage stored in the second capacitor C12 is the source of the fourth transistor T14 through the third node N13. Since the fourth transistor T14 is turned on by a signal applied to the gate line GL, the voltage stored in the second capacitor C12 is transferred to the reference voltage terminal Vref. At this time, the organic light emitting diode OLED11 does not emit light.

Here, the voltage of the second node N12 is a value obtained by adding the threshold voltage of the third transistor T13 to the data voltage, and the data voltage is defined as, for example, a high level signal in black and a low level signal in white. Can be.

In addition, the voltage of the second node N12 may vary according to the mobility of the third transistor T13. If the mobility of the third transistor T13 is high, a voltage drop occurs quickly at the second node N12, as shown by 'a' in FIG. 2, and the mobility of the third transistor T13 is low. In this case, as in 'b' of FIG. 2, the voltage drop at the second node N12 gradually occurs.

Subsequently, when, for example, a low level signal is applied to the control line CL and a high level signal is applied to the gate line GL during the emission period C, the second line connected to the control line CL is applied. The transistor T12 is turned on and the first transistor T11 and the fourth transistor T14 connected to the gate line GL are turned off.

Then, the fourth transistor T14 is turned on by the voltage of the first node N11, and the power supply voltage VDD is connected to the anode of the organic light emitting diode OLED11 through the fourth transistor T14. When applied, the organic light emitting diode OLED11 emits light.

In this case, the voltage of the first node N11, that is, the voltage Vg applied to the gate of the fourth transistor T14 may be expressed as in Equation 1 below.

[Equation 1]

In addition, the current I _OLED flowing through the organic light emitting diode OLED11 may be expressed by Equation 2.

&Quot; (2) "

Here, the current I _OLED flowing in the organic light emitting diode OLED11 may be expressed differently according to the values of the first and second capacitors C11 and C12. If the value of the second capacitor C12 is greater than the value of the first capacitor C11, the current I _OLED flowing through the organic light emitting diode OLED11 may be expressed as K / 2. In addition, when the value of the second capacitor C12 is smaller than the value of the first capacitor C11, the current I _OLED flowing through the organic light emitting diode OLED11 may be expressed by Equation 3 below.

&Quot; (3) "

Here, K is expressed as 1/2 占 μpGgW / L, and μp indicates the mobility of the P-type transistor and Cg indicates the gate capacitance, respectively.

As described above, in the exemplary embodiment of the present invention, as shown in FIG. 2, the mobility of the third transistor T13 is compensated for in the data write period B, but the threshold voltage Vth of the third transistor T13 is compensated for. There is no compensation interval for the deviation. Accordingly, when the organic light emitting display device is driven, short-term afterimages may occur due to device characteristics. The variation in the mobility and threshold voltage of the transistor may be caused by the laser scan unevenness during the laser crystallization process during transistor formation.

In detail, the current I _OLED flowing through the organic light emitting diode OLED11 is very sensitive to the values of the first and second capacitors C11 and C12, as shown in Equation 2, wherein the second capacitor C12 ) Is greater than the value of the first capacitor C11, the current I _OLED flowing through the organic light emitting diode OLED11 is represented by K / 2, so that image data information disappears and gray scales cannot be expressed.

In addition, when the value of the second capacitor C12 is smaller than the value of the first capacitor C11, the current I _OLED flowing through the organic light emitting diode OLED11 is equal to the power source voltage VDD and the third power source. There is no compensation section for the deviation of the threshold voltage of the three transistors T13. In fact, when the organic light emitting display device is driven, short-term afterimage and uneven image quality in the low gradation region are generated due to device characteristics.

In another embodiment of the present invention, the organic light emitting display device further includes a threshold voltage compensation period after an initialization period in one frame. Detailed description thereof will be described with reference to FIG. 4.

3 is a view illustrating a driving circuit of an organic light emitting display device according to another exemplary embodiment of the present invention.

Referring to FIG. 3, each unit pixel 210 according to another exemplary embodiment of the present invention may include a first transistor T21 to a fourth transistor T24, first and second capacitors C21 and C22, and an organic field. The light emitting device OLED21 is included.

The gate of the first transistor T21 is connected to the gate line GL to which the gate signal is applied, the gate source is connected to the data line DL to which the data signal is applied, and the drain is one end of the first capacitor C21. Connected to the gate signal and turned on according to the gate signal to output a data signal.

The gate of the second transistor T22 is connected to the control line CL to which the control signal is applied, the source is connected to the power supply voltage VDD, the drain is connected to the first node N21, and according to the control signal. Output the power supply voltage.

A gate of the third transistor T23 is connected to the gate line GL, a source is connected to a reference voltage line VREF to which a reference voltage is applied, a drain is connected to the second node N22, and is connected to a gate signal. Output the reference voltage accordingly.

A gate of the fourth transistor T24 is connected to the second node N22, a source is connected to the first node N21, a drain is connected to an anode of the organic light emitting diode OLED21, and an organic light emitting diode Provides a current to drive OLED21.

In addition, one end of the first capacitor C21 is connected to the drain of the first transistor T21, and the other end thereof is connected to the first node N21 to store a data signal.

One end of the second capacitor C22 is connected to the first node N11, the other end is connected to the second node N22, and provides a constant bias voltage to the gate of the fourth transistor T24.

The anode of the organic light emitting diode OLED11 is connected to the drain of the fourth transistor T24 and the cathode is connected to the ground voltage GND.

3 and 4, the driving of the organic light emitting display device according to another exemplary embodiment will be described. 4 is a timing diagram of a driving circuit of an organic light emitting display device according to another exemplary embodiment of the present invention.

3 and 4, an organic light emitting display device according to another exemplary embodiment of the present invention may include an initialization section A ′, a threshold voltage compensation section B ′, a data writing section C ′, and a frame during one frame. Light emission period D '.

First, when a low level signal is applied to the gate line GL and the control line CL during the initialization period A ', the first and third transistors T21 and T23 connected to the gate line GL are turned on. On, the second transistor T22 connected to the control line CL is turned on.

Then, the first transistor T21 is turned on to charge the first capacitor C21 with the data voltage, and the third transistor T23 is turned on to apply the bias voltage, that is, the reference voltage, to the second capacitor C22. do. As the second transistor T22 is turned on and a voltage higher than the second node N22 is applied to the first node N21, for example, a power supply voltage VDD, the fourth transistor T24 is turned on. On, the organic light emitting diode OLED21 emits light initially.

Next, during the threshold voltage compensation period B ', the low level signal is applied to the gate line GL, and the first and third transistors T21 and T23 connected thereto are continuously turned on, and the control line The high level signal is applied to CL and the second transistor T22 connected thereto is turned off.

At this time, the second transistor T22 is turned off and the first node N21 is in a floating state so that the power supply voltage VDD is not applied and the self operation of the fourth transistor T24 is performed. As the voltage is discharged, the voltage of the first node N21 is set to a value (VREF + | Vth |) of which the threshold voltage of the fourth transistor T24 is added to the reference voltage. At this time, if it is assumed that the reference voltage is 0V, for example, the voltage of the first node N21 actually has the threshold voltage of the fourth transistor T24. Here, the organic light emitting diode OLED11 does not emit light.

During the data write period C ', a low level signal is applied to the gate line GL, so that the first and third transistors T21 and T23 remain turned on, and the control line CL also has a high level. The signal is applied to keep the second transistor T22 turned off. In this case, the data voltage of the high level signal is applied to the data line DL, and the applied data voltage is distributed by the first and second capacitors C11 and C12, and the voltage of the first node N21 is It can be expressed as Equation 4.

&Quot; (4) "

Here, Vint represents a precharge voltage E ', where the precharge voltage E' may have a value between the minimum value and the maximum value of the data voltage, and ΔV at the time of writing the data voltage. Shows the voltage deviation of the source node discharged according to the mobility of the fourth transistor T24, that is, the first node N21, and compensates for the mobility variation of the fourth transistor T24 by Equation 4. can do.

Finally, when a low level signal is applied to the control line CL and a high level signal is applied to the gate line GL during the emission period D ', for example, the second connected to the control line CL. The transistor T22 is turned on, and the first transistor T21 and the third transistor T23 connected to the gate line GL are turned off.

Then, the fourth transistor T24 is turned on by the voltage stored in the second capacitor C22, that is, the voltage of the second node N22, and the power source voltage VDD is turned on through the fourth transistor T24. The OLED is applied to an anode of the light emitting device OLED21 to emit light. At this time, the second transistor T22 is turned on so that the voltage of the first node N21 rises to the power supply voltage VDD. As a result, the voltage of the second node N22 increases due to a charge conservation law. It can be expressed as shown in Equation 5.

[Equation 5]

Here, when the organic light emitting diode OLED22 emits light, the voltage of the first node N21 increases to the power supply voltage VDD, and in order to maintain the existing charge amount in the second capacitor C22, Similarly, the voltage of the second node N22 is obtained.

In addition, when the organic light emitting diode OLED22 emits light, a difference between the source node and the gate node of the fourth transistor T24, that is, the first node N21 and the second node N22 is finally expressed by Equation 6 below. Can be expressed.

&Quot; (6) "

Finally, the saturation current I _OLED may be expressed as shown in Equation 7, wherein the threshold voltage Vth and the power supply voltage VDD of the fourth transistor T24 are erased to erase the data voltage and the initial voltage. The current may be represented by the ratio of the precharge voltage Vint and the first and second capacitors C21 and C22. Here, the variation in mobility of the fourth transistor T24 may be compensated for by ΔV.

[Equation 7]

As described above, in another embodiment of the present invention, the third transistor T23 is disposed between the reference voltage line VREF and the fourth transistor T24 in order to implement the fourth transistor T24 as a source follower. In this case, a constant bias voltage is applied to the gate of the fourth transistor T24 from the initial period and the period A 'to the data write period C'.

In another embodiment of the present invention, the third transistor T23 is disposed between the reference voltage line VREF and the fourth transistor T24 so that the third transistor T23 is disposed in the initialization period A 'and the threshold voltage compensation period B'. The data write operation can be performed while maintaining the drain of the first transistor T21 of the one capacitor C21 at a predetermined voltage.

In another embodiment of the present invention, a write operation of a node and data connected to the drain of the first transistor T21 and one end of the first capacitor C21 may be implemented using one data line.

 In another embodiment of the present invention, as shown in Equation 7, the organic light emitting diode OLED22 is erased from the power supply voltage VDD when light is emitted and is independent of the power supply voltage VDD. drop) can be compensated.

In another embodiment of the present invention, as shown in FIG. 4, the threshold voltage compensation section B 'exists between the initialization section A' and the data writing section C ', and thus occurs when the organic light emitting display device is driven. It can minimize image quality unevenness in short-term afterimage and low gradation region.

Further, in another embodiment of the present invention, each unit pixel structure is simple, so that the aperture ratio of the organic light emitting display device can be improved, thereby improving the lifespan of the organic light emitting display device, and also improving the yield in manufacturing the substrate. .

In addition, according to another embodiment of the present invention, the gate driver can be simply designed because the number of control signals for controlling the transistors in each unit pixel is small, which causes the organic light emitting display having a narrow bezel. The device can be implemented.

However, as the second transistor T22 is turned on in the initialization period A 'and the voltage higher than the second node N22 is applied to the first node N21, the fourth transistor T24 is turned on and thus is induced. There is a problem that the electroluminescent element OLED21 emits light.

In another embodiment of the present invention, a transistor for suppressing light emission of the organic light emitting diode OLED21 is further provided in a circuit of the organic light emitting diode in the initialization section A '. .

5 is a diagram illustrating a driving circuit of an organic light emitting display device according to another embodiment of the present invention.

Referring to FIG. 5, each unit pixel 310 according to another exemplary embodiment of the present invention may include the first transistor T31 to the fifth transistor T35, the first and second capacitors C31 and C32, and the organic layer. And an electroluminescent element OLED31.

Here, the first to fourth transistors T31 to T34 and the first and second capacitors C31 and C32 have the same structure as other embodiments of the present invention.

In another embodiment of the present invention, the fifth transistor T35 is further provided in the circuit of the organic light emitting diode to suppress light emission of the organic light emitting diode OLED31 in the initialization section A '.

In this case, the gate of the fifth transistor T35 is connected to the gate line GL, is turned on by receiving a predetermined voltage from the gate line GL, the source is connected to the reference voltage line VREF, and the drain is organic. One end of the electroluminescent element OLED31, ie, the anode, is connected.

In addition, the driving of the organic light emitting display device according to another embodiment of the present invention is the same as the driving of the organic light emitting display device according to another embodiment of the present invention.

However, in another embodiment of the present invention, the fifth transistor T35 is further turned on during the initialization period A 'to suppress light emission of the organic light emitting diode OLED31.

In detail, when the low level signal is applied to the gate line GL and the control line CL during the initialization period A ', the first and third transistors T31 and 3 are connected to the gate line GL. T33 and the fifth transistor T35 are turned on, and the second transistor T32 connected to the control line CL is turned on.

Then, since the third transistor T33 is turned on and the low level signal is applied to the second node N32, the fourth transistor T34 is turned on, so that the current I _{OLED is} connected to the second transistor T32. The reference voltage line VREF flows through the fourth and fifth transistors T34 and T35. Accordingly, the voltage of the ground voltage GND connected to the reference voltage line VREF and the cathode of the organic light emitting diode OLED31 may be maintained at the same potential as 0V. Accordingly, the current I _OLED applied to the anode of the organic light emitting diode OLED31 can be reduced. Accordingly, light emission of the organic light emitting diode OLED31 may be suppressed because the current I _OLED applied to the anode of the organic light emitting diode OLED31 is reduced.

Many details are set forth in the foregoing description but should be construed as illustrative of preferred embodiments rather than to limit the scope of the invention. Accordingly, the invention is not to be determined by the embodiments described, but should be determined by equivalents to the claims and the appended claims.

CL: control line GL: gate line
DL: data line VREF: reference line
T11, T21, T31: first transistor T12, T22, T32: second transistor
T13, T23, and T33: third transistors T14, T24, and T34: fourth transistors
T35: fifth transistor C11, C21, C31: first capacitor
C12, C22, C32: second capacitor
OLED11, OLED21, OLED31: organic light emitting diode

Claims (16)

In the driving circuit of the organic light emitting display device for controlling the current supplied to the organic light emitting element,
A first transistor connected to a gate line to which a gate signal is applied, a source connected to a data line to which a data signal is applied, and a first transistor configured to output the data signal according to the gate signal;
A second transistor connected to the gate line, a source connected to a reference voltage line to which a reference voltage is applied, and outputting the reference voltage according to the gate signal;
A third transistor having a gate connected to a control line to which a control signal is applied, a source connected to a power supply voltage line applying a power supply voltage, and outputting the power supply voltage according to the control signal;
A first capacitor having one end connected to the drain of the first transistor and the other end connected to the drain of the third transistor and storing the data signal;
A fourth transistor connected to a drain of the second transistor and a source connected to a drain of the third transistor, the fourth transistor providing a current for driving the organic light emitting diode;
A second capacitor having one end connected to the drain of the third transistor and the other end connected to the drain of the second transistor, the second capacitor providing a constant bias voltage to the gate of the fourth transistor; And
And an anode connected to the drain of the fourth transistor, and a cathode connected to the ground voltage line to which the ground voltage is applied, wherein the organic light emitting display device includes an organic light emitting display device. The method of claim 1,
A data voltage is applied to the source of the first transistor, a reference voltage is applied to the source of the second transistor, and a power supply voltage is applied to the source of the third transistor. The method of claim 1,
When the gate-on signal is applied to the gates of the first and second transistors, and the control-on signal is applied to the gates of the third transistors to turn on the first to third transistors, the drain voltage of the third transistors is turned on. Is higher than the drain voltage of the second transistor. The method of claim 1,
The gate-on signal is applied to the gates of the first and second transistors, and the control-off signal is applied to the gates of the third transistor so that the first and second transistors are turned on and the third transistor is turned off. In this case, the drain voltage of the third transistor is set to a value obtained by adding a threshold voltage of the fourth transistor to a reference voltage. The method of claim 1,
A gate is connected to the gate line, a source is connected to the reference voltage line, a drain is connected to a drain of the fourth transistor, and a fifth transistor is configured to suppress initial emission of the organic light emitting diode. A drive circuit for an organic light emitting display device. The method of claim 5,
A gate-off signal is applied to the gates of the first and second transistors, a control-on signal is applied to the gates of the third transistor, and the first and second transistors are turned off, and the third transistor is turned on. In this case, a current for driving the organic light emitting display device flows through the second transistor, the fourth transistor and the fifth transistor to the reference voltage line, characterized in that the driving circuit of the organic light emitting display device. The method according to claim 6,
And the potential of the reference voltage line and the potential of the ground voltage line connected to the cathode of the organic light emitting diode are maintained at the same potential. The method of claim 1,
The fourth transistor is a source follower (source follower), characterized in that the driving circuit of the organic light emitting display device. The method of claim 1,
The first to fourth transistors are formed of any one selected from a P-type transistor, an N-type transistor, amorphous silicon (a-Si), and an oxide (oxide). The method of claim 1,
The reference voltage is a driving circuit of the organic light emitting display device, characterized in that the ground voltage. A plurality of control lines, a plurality of reference voltage lines, a plurality of gate lines, a plurality of data lines formed to intersect the plurality of gate lines, and a plurality of data lines formed in an area where the plurality of gate lines and the plurality of data lines cross each other An organic light emitting display device comprising a plurality of pixels in a matrix form including a driving transistor for supplying current to an organic light emitting device.
An initialization step of charging a data voltage and a bias voltage to first and second capacitors connected to the driving transistor by applying a control on signal and a gate on signal to the plurality of control lines and the plurality of gate lines, respectively;
A threshold voltage compensation step of applying a control off signal to the plurality of control lines to set a source voltage of the driving transistor to a value obtained by adding a threshold voltage of the driving transistor to a reference voltage;
Writing data in which the data voltages applied through the plurality of data lines are distributed by the first and second capacitors; And
And applying the control on signal and the gate off signal to the plurality of control lines and the plurality of gate lines, respectively, to turn on the driving transistor to supply current to the organic light emitting diode. A method of driving an organic light emitting display device. The method of claim 11,
The bias voltage is a driving method of an organic light emitting display device, characterized in that the voltage applied to the reference voltage line. The method of claim 11,
And the initializing step changes the path of the current supplied to the organic light emitting display device to the reference voltage line to suppress initial light emission of the organic light emitting display device. The method of claim 13,
And the potential of the reference voltage line and the potential of the ground voltage line connected to the cathode of the organic light emitting diode are maintained at the same potential. The method of claim 11,
The driving transistor is a source follower (source follower) characterized in that the driving method of the organic light emitting display device. The method of claim 11,
And the driving transistor is formed of any one selected from a P-type transistor, an N-type transistor, amorphous silicon (a-Si), and an oxide.

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