KR102480129B1 - Organic light emitting diode display device - Google Patents

Abstract

The present invention provides an organic light emitting display device including a display panel and a gate driver. In such an organic light emitting display device, a plurality of pixels are disposed on a display panel, and each pixel includes an organic light emitting diode, a driving transistor for driving the organic light emitting diode, a switching transistor located between the gate node of the driving transistor and the data line, and a driving transistor. and a sensing transistor positioned between the source node or drain node of the transistor and the sensing line. Further, in the organic light emitting display device, the gate driver supplies a first voltage to the gate node of the switching transistor and the sensing transistor in the display driving section and supplies a voltage different from the first voltage to the gate node of the switching transistor and the sensing transistor in the display sensing section. 2 supply voltage.

Description

Organic light emitting display {ORGANIC LIGHT EMITTING DIODE DISPLAY DEVICE}

The present invention relates to an organic light emitting display device.

As the information society develops, the demand for display devices for displaying images is increasing in various forms, and recently, liquid crystal display devices, plasma display devices, organic light emitting display devices ( Various display devices such as Organic Light Emitting Display Device) have been utilized.

Among them, the organic light emitting display device uses an organic light emitting diode that emits light by itself, and thus has advantages such as fast response speed, high luminous efficiency, luminance, and viewing angle.

Meanwhile, as the driving time of the organic light emitting display device increases, degradation of organic light emitting diodes (OLEDs) included in each pixel and circuit elements such as transistors may progress. In addition, according to such deterioration, characteristic values (eg, threshold voltage, mobility, etc.) of organic light emitting diodes (OLEDs) and circuit elements such as transistors may change.

Changes in characteristic values of these circuit elements may cause changes in luminance of pixels. In addition, such a change in characteristic values of circuit elements may cause differences in characteristic values between pixels, resulting in non-uniform image quality.

In order to solve this problem, the organic light emitting display device may further include a circuit for sensing and compensating for a characteristic value or characteristic change amount of each pixel. For example, a sensing line is connected to each pixel, and the organic light emitting display device may sense a characteristic value of each pixel through the sensing line and compensate for the changed characteristic value.

However, in the process of sensing the characteristic value of a pixel, noise may be generated and the characteristic value may be erroneously sensed. Also, such erroneous sensing may cause erroneous compensation. For example, the organic light emitting display device may compensate for normal pixels to make the gray level brighter or darker. Alternatively, the organic light emitting display device may cause image quality defects such as a defect in a horizontal line by miscompensating only a specific pixel or a pixel in a specific line.

Against this background, an object of the present invention is to provide a noise-robust organic light emitting display device technology. More specifically, it is to provide a technology that allows an organic light emitting display device to be less affected by noise when sensing characteristic values of pixels.

In order to achieve the above object, in one aspect, the present invention provides an organic light emitting display device including a display panel and a gate driver. In such an organic light emitting display device, a plurality of pixels are disposed on a display panel. Each pixel includes an organic light emitting diode, a driving transistor driving the organic light emitting diode, a switching transistor positioned between the gate node of the driving transistor and the data line, and a driving transistor. It includes a sensing transistor positioned between the source node or drain node of and the sensing line. Further, in the organic light emitting display device, the gate driver supplies a first voltage to the gate node of the switching transistor and the sensing transistor in the display driving section and supplies a voltage different from the first voltage to the gate node of the switching transistor and the sensing transistor in the display sensing section. 2 supply voltage.

In another aspect, the present invention provides an organic light emitting display device including a display panel and a gate driver. In such an organic light emitting display device, a plurality of pixels are disposed on a display panel. Each pixel includes an organic light emitting diode, a driving transistor driving the organic light emitting diode, a switching transistor positioned between the gate node of the driving transistor and the data line, and a driving transistor. It includes a sensing transistor positioned between the source node or drain node of and the sensing line. Further, in the organic light emitting display device, the gate driver supplies a first voltage to the gate node of the switching transistor and supplies a second voltage different from the first voltage to the gate node of the sensing transistor.

As described above, according to the present invention, the influence of noise can be reduced when the organic light emitting display device senses characteristic values of pixels.

1 is a configuration diagram of an organic light emitting display device according to an exemplary embodiment.
FIG. 2 is a diagram illustrating an internal structure of a pixel shown in FIG. 1 .
FIG. 3 is a diagram illustrating a state in which the switching transistor and the sensing transistor of FIG. 2 are turned on.
4 is a diagram showing turn-on voltage and turn-on resistance according to sections.
5 is a diagram showing a first example of a circuit configuration of a power management unit.
6 is a diagram showing a second example of a circuit configuration of a power management unit.
7 is a diagram showing a third example of a circuit configuration of a power management unit.
8 is a diagram illustrating a pixel structure in which a switching transistor and a sensing transistor are turned on by different signals.
9 is a diagram showing a fourth example of a circuit configuration of a power management unit.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. In adding reference numerals to components of each drawing, it should be noted that the same components have the same numerals as much as possible even if they are displayed on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description will be omitted.

Also, terms such as first, second, A, B, (a), and (b) may be used in describing the components of the present invention. These terms are only used to distinguish the component from other components, and the nature, order, or order of the corresponding component is not limited by the term. When an element is described as being “connected,” “coupled to,” or “connected” to another element, that element is directly connected or connectable to the other element, but there is another element between the elements. It will be understood that elements may be “connected”, “coupled” or “connected”.

1 is a configuration diagram of an organic light emitting display device according to an exemplary embodiment.

Referring to FIG. 1 , an organic light emitting display device 100 may include a panel 110 , a gate driver 120 , a data driver 130 , a timing controller 140 , a power manager 150 , and the like.

A plurality of data lines DL, a plurality of gate lines GL, and a plurality of sensing lines SL are disposed on the panel 110, and the data lines DL, the gate lines GL, and the sensing lines SL and A plurality of connected pixels SP may be disposed.

The gate driver 120 may supply a scan signal of a turn-on voltage or a turn-off voltage to the gate line GL under the control of the timing controller 140 . When the scan signal of the turn-on voltage is supplied to the pixel SP, the corresponding pixel SP is connected to the data line DL, and when the scan signal of the turn-off voltage is supplied to the pixel SP, the corresponding pixel SP and the data line (DL) is disconnected.

The data driver 130 supplies data voltage to the data line DL. The data voltage supplied to the data line DL is supplied to the pixel SP connected to the data line DL according to the scan signal.

The data driver 130 receives image data from the timing controller 140 and converts the image data to generate data voltages.

The timing controller 140 may supply various control signals to the gate driving unit 120 , the data driving unit 130 , and the power management unit 150 .

The timing controller 140 starts scanning according to the timing implemented in each frame, and converts externally input image data according to the data signal format used by the data driver 130 . The timing controller 140 may output the converted image data to the data driver 130 and control the data driver 130 at an appropriate time according to the scan.

The power management unit 150 may generate and manage voltages required by the panel 110 , the gate driver 120 , the data driver 130 , and the timing controller 140 . For example, the turn-on voltage or turn-off voltage supplied to the gate line GL by the gate driver 120 may be generated and managed by the power management unit 150 .

Each of the gate driving unit 120, the data driving unit 130, the timing controller 140, and the power management unit 150 may include one or more integrated circuits. For example, the data driver 130 may include at least one Source Driver Integrated Circuit (SDIC).

Meanwhile, at least two of the gate driver 120, the data driver 130, the timing controller 140, and the power management unit 150 may be implemented as one integrated circuit. For example, the data driver 130 and the timing controller 140 may be implemented as one integrated circuit.

The gate driver 120, the data driver 130, the timing controller 140, and the power management unit 150 may be implemented in other forms. For example, some functions of the data driver 130 and the timing controller 140 is implemented as one integrated circuit, and the remaining functions of the data driver 130 may be implemented as separate integrated circuits.

Meanwhile, the data driver 130 may receive a characteristic sensing signal of each pixel SP through the sensing line SL.

The component for receiving the characteristic sensing signal of each pixel (SP) through the sensing line (SL) may be provided separately from the data driver 130, but below will be described in an embodiment in which this component is integrated into the data driver 130. explain about The organic light emitting display device 100 may further include a characteristic sensing unit (not shown) as needed and receive a characteristic sensing signal of each pixel through the characteristic sensing unit (not shown).

FIG. 2 is a diagram illustrating an internal structure of a pixel shown in FIG. 1 .

Referring to FIG. 2 , the pixel SP includes an organic light emitting diode (OLED), a driving transistor (DRT) that drives the organic light emitting diode (OLED), and a gate of the driving transistor (DRT). It may include a switching transistor (SWT) to transfer the data voltage to the second node (N2) corresponding to the node and a storage capacitor (Cstg) to maintain the data voltage for one frame time. there is.

An organic light emitting diode (OLED) may include a first electrode (eg, an anode electrode or a cathode electrode), an organic layer, and a second electrode (eg, a cathode electrode or an anode electrode).

The driving transistor DRT drives the organic light emitting diode (OLED) by supplying a driving current to the organic light emitting diode (OLED).

The first node N1 of the driving transistor DRT may be electrically connected to the first electrode of the organic light emitting diode OLED, and may be a source node or a drain node. The second node N2 of the driving transistor DRT may be electrically connected to a source node or a drain node of the switching transistor SWT and may be a gate node of the driving transistor DRT. The third node N3 of the driving transistor DRT may be electrically connected to a driving voltage line (DVL) supplying the driving voltage EVDD, and may be a drain node or a source node.

The drive transistor DRT and the switching transistor SWT may be implemented as N-type or P-type as shown in the example of FIG. 2 .

The switching transistor SWT is electrically connected between the data line DL and the second node N2 of the driving transistor DRT, and may be controlled according to a scan signal supplied through the gate line GL. In particular, the switching transistor SWT may be turned on by the turn-on voltage Vgh supplied through the gate line GL.

When the switching transistor SWT is turned on, the data line DL is connected to the second node N2 of the driving transistor DRT, and the data voltage Vdata is supplied to the second node N2.

The storage capacitor Cstg may be electrically connected between the first node N1 and the second node N2 of the driving transistor DRT.

The storage capacitor Cstg may be a parasitic capacitor (eg, Cgs or Cgd) that is an internal capacitor existing between the first node N1 and the second node N2 of the driving transistor DRT. , may be an external capacitor intentionally designed outside the driving transistor (DRT).

Meanwhile, in the organic light emitting display device 100, as the driving time of each pixel SP increases, circuit elements such as the organic light emitting diode (OLED) and the driving transistor (DRT) may be degraded. .

Accordingly, inherent characteristic values (eg, threshold voltage, mobility, etc.) of circuit elements such as organic light emitting diodes (OLEDs) and driving transistors (DRTs) may change. A change in the characteristic value of the circuit element may cause a change in luminance of the corresponding pixel SP. In addition, the degree of change in characteristic values between circuit elements may be different depending on the degree of deterioration of each circuit element.

Here, the characteristic value of the circuit element (hereinafter also referred to as “pixel characteristic value”) may include, for example, the threshold voltage and mobility of the driving transistor DRT, and the like, and in some cases, the organic light emitting diode (OLED) It may also include a threshold voltage.

The organic light emitting display device 100 has a sensing function that senses the characteristic value or characteristic change amount of the pixel SP and a compensation function that compensates for the luminance change of the pixel SP and the luminance deviation between the pixels SP using the sensing result. can provide

The organic light emitting display device 100 includes a pixel SP structure suitable for sensing and compensating for a characteristic value or characteristic change amount of the pixel SP, and a compensation circuit including a sensing and compensating structure.

Referring to FIG. 2 , each pixel SP disposed on the panel 110, for example, in addition to an organic light emitting diode (OLED), a driving transistor (DRT), a switching transistor (SWT) and a storage capacitor (Cstg), senses A transistor (SENT: Sensing Transistor) may be further included.

Referring to FIG. 2 , the sensing transistor SENT is electrically connected between the first node N1 of the driving transistor DRT and the sensing line SL that supplies a reference voltage (Vref), and is a gate node. It can be controlled by receiving a sensing signal, which is a kind of raw scan signal.

The scan signal supplied to the switching transistor SWT and the sensing signal supplied to the sensing transistor SENT may be different signals or may be the same signal.

Referring to FIG. 2 , gate nodes of the switching transistor SWT and the sensing transistor SENT are connected to the same gate line GL. In this structure, the scan signal and the sensing signal may be the same signal.

In the structure shown in FIG. 2 , the sensing transistor SENT may be turned on by the turn-on voltage Vgh supplied through the gate line GL.

When the sensing transistor SENT is turned on, the sensing line SL and the first node N1 of the driving transistor DRT are connected, and the reference voltage Vref may be supplied to the first node N1.

Also, the voltage of the first node N1 formed after supplying the reference voltage Vref may be transferred to the data driver 130 through the sensing line SL. Specifically, the data driver 130 receives the voltage or current formed at the first node N1 - the source node of the driving transistor DRT as a characteristic sensing signal and senses the characteristic value of the pixel SP by using the voltage or current. can

Meanwhile, parasitic capacitance may be generated in the sensing line SL or an external capacitor may be added by design. In addition, a turn-on resistance rds-on is formed in the sensing transistor SENT, and the turn-on resistance and the capacitance of the sensing line SL may function like a filter.

FIG. 3 is a diagram illustrating a state in which the switching transistor and the sensing transistor of FIG. 2 are turned on.

When the switching transistor SWT and the sensing transistor SENT are turned on by the turn-on voltage Vgl, a turn-on resistance may be formed in each of the transistors SWT and SENT.

The turn-on resistance of the sensing transistor SENT may form a low pass filter together with the capacitor Cs formed on the sensing line SL. In addition, the characteristic sensing signal Sds transmitted from the pixel SP may filter out noise while passing through such a low pass filter.

Here, in order to remove more noise from the low pass filter, the turn-on resistance of the sensing transistor SENT or the capacitor Cs of the sensing line SL needs to be increased. Since the value of the capacitor Cs formed on the sensing line Cs is not changed by control, the turn-on resistance of the sensing transistor SENT needs to be substantially increased in order to improve noise removal capability.

In order to increase the turn-on resistance of the sensing transistor SENT, the sensing transistor SENT must be in a state where it is not fully turned on. However, since the switching transistor (SWT) and the sensing transistor (SENT) are turned on by the same turn-on voltage (Vgh), the conventional organic light emitting display controls the turn-on voltage (Vgh) in a direction in which the sensing transistor (SENT) is completely turned on. .

In detail, since the size of the storage capacitor Cstg is large, the turn-on resistance of the switching transistor SWT must be small in order to drive the driving transistor DRT quickly. Further, in order to reduce the turn-on resistance of the switching transistor SWT, the turn-on voltage Vgh of the switching transistor SWT must be high. For this reason, the conventional organic light emitting display device increases the turn-on voltage (Vgh) supplied to the switching transistor (SWT) and the sensing transistor (SENT) (in the N type), so that the switching transistor (SWT) and the sensing transistor (SENT) was fully turned on.

In the organic light emitting display device 100 according to an exemplary embodiment, the turn-on voltage Vgh may be differently controlled by dividing the sections. Specifically, the organic light emitting display device 100 completely turns on the switching transistor SWT by controlling the turn-on voltage Vgh in a section where the switching transistor SWT needs to be completely turned on. Further, the organic light emitting display device 100 does not completely turn on the sensing transistor SENT through control of the turn-on voltage Vgh in a section where the turn-on resistance of the sensing transistor SENT is to be increased.

4 is a diagram showing turn-on voltage and turn-on resistance according to sections.

Referring to FIG. 4 , the organic light emitting display device 100 may include a display driving section and a display sensing section.

In the display driving period, the organic light emitting display device 100 displays an image on the panel 110 by supplying a data voltage to each pixel SP. In the display sensing period, the organic light emitting display device 100 receives a characteristic sensing signal from each pixel SP and senses a characteristic value of each pixel using the characteristic sensing signal.

The gate driver 120 of the organic light emitting display device 100 may supply the first voltage Vgh1 to gate nodes of the switching transistor SWT and the sensing transistor SENT in the display driving period. Also, the gate driver 120 may supply a second voltage Vgh2 different from the first voltage Vgh1 to gate nodes of the switching transistor SWT and the sensing transistor SENT in the display sensing period.

2 shows that the second voltage Vgh2 is lower than the first voltage Vgh1. When the switching transistor SWT and the sensing transistor SENT are N-type transistors, the second voltage Vgh2 is the first voltage. (Vgh1) may be lower. Conversely, when the switching transistor SWT and the sensing transistor SENT are P-type transistors, the second voltage Vgh2 may be higher than the first voltage Vgh1. An embodiment in which the second voltage Vgh2 is lower than the first voltage Vgh1 will be described below.

When the second voltage Vgh2 is supplied compared to the first voltage Vgh1, the turn-on resistance of the sensing transistor SENT may further increase.

As the turn-on resistance further increases in the display sensing period in which the characteristic sensing signal is received, noise removal capability of the low-pass filter formed by the turn-on resistance of the sensing transistor SENT and the capacitor of the sensing transistor SENT may be further improved.

Meanwhile, when the transistor is turned on in a saturation region rather than a linear region, turn-on resistance may increase. Accordingly, the gate driver 120 may turn on the switching transistor SWT in the linear region in the display driving section and turn on the sensing transistor SENT in the saturation region in the display sensing section.

The turn-on voltage Vgh supplied from the gate driver 120 may be generated by the power management unit 150 .

5 is a diagram showing a first example of a circuit configuration of a power management unit.

Referring to FIG. 5, the power management unit 550 includes a boost circuit including an inductor L1, a switch S1, a diode D1, and an output capacitor C1, and uses the boost circuit to turn-on voltage. (Vgh) can be generated.

In this boost circuit, the output voltage is determined by the PWM (Pulse Width Modulation) duty of the switch S1, and the power management unit 550 controls this PWM duty to output the first voltage Vgh1 as the turn-on voltage or to output the second voltage Vgh1 as the turn-on voltage. A voltage (Vgh2) can be output.

The power management unit 550 may receive control information (PCS: Power Control Signal) from the timing controller 140, and the power management unit 550 supplies voltage to the sensing transistor (SENT) according to the control information (PCS). may be changed from the first voltage Vgh1 to the second voltage Vgh2.

6 is a diagram illustrating a second example of a circuit configuration of a power management unit.

Referring to FIG. 6 , the power management unit 650 may further include a voltage divider circuit for sensing an output voltage in addition to the boost circuit shown in FIG. 5 , and may sense the output voltage through the voltage divider circuit to perform feedback control.

The voltage divider circuit may include a plurality of resistors R1, R2, and R3 and a switch Sr. Also, the power management unit 650 may change the output voltage from the first voltage Vgh1 to the second voltage Vgh2 by changing the impedance of the voltage divider circuit by controlling the switch Sr.

For example, the voltage divider circuit includes a first resistor (R1) and a second resistor (R2) connected in series between the output voltage and the ground, and a third resistor (R3) and a switch (S2) connected in series with each other It may be connected in parallel to the second resistor (R2).

The controller 652 of the power management unit 650 may feedback-control the output voltage using the feedback voltage Vfb formed at the contact point of the first resistor R1 and the second resistor R2. In this structure, the impedance of the power distribution circuit changes while the third resistor R3 is connected in parallel to or not connected to the second resistor R2 according to the switch control signal transmitted to the switch Sr. In addition, the feedback voltage Vfb is changed according to the impedance change of the power distribution circuit, and accordingly, the power management unit 650 can selectively generate the first voltage Vgh1 and the second voltage Vgh2.

7 is a diagram showing a third example of a circuit configuration of a power management unit.

Referring to FIG. 7 , the power management unit 750 includes a first boost circuit (BC1) including a first inductor (L1), a first switch (S1), a first diode (D1) and a first output capacitor (C1). can include Further, the power management unit 750 may further include a second boost circuit BC2 including a second inductor L2, a second switch S2, a second diode D2, and a second output capacitor C2. can

The power management unit 750 may simultaneously generate the first voltage Vgh1 and the second voltage Vgh2 using the first boost circuit BC1 and the second boost circuit BC2. Specifically, the first boost circuit BC1 may generate the first voltage Vgh1, and the second boost circuit BC2 may generate the second voltage Vgh2 separately from the first boost circuit BC1.

The power management unit 750 further includes a selection circuit 752 and supplies one of the first voltage Vgh1 and the second voltage Vgh2 to the gate driver 120 using the selection circuit 752. can Also, the gate driver 120 may supply one selected voltage to the gate node of the sensing transistor SENT.

Meanwhile, in the above embodiment, the switching transistor SWT and the sensing transistor SENT are described as being turned on by the same signal, but the switching transistor SWT and the sensing transistor SENT may be turned on by different signals, respectively.

8 is a diagram illustrating a pixel structure in which a switching transistor and a sensing transistor are turned on by different signals.

Referring to FIG. 8 , two gate lines GLa and GLb may be connected to the pixel SP. Among the two gate lines GLa and GLb, the first gate line GLa supplies the first voltage Vgh1 to the gate node of the switching transistor SWT, and the second gate line GLb supplies the sensing transistor SENT ) may supply the second voltage Vgh2 to the gate node.

In this structure, the gate driver 120 may supply the first voltage Vgh1 to the gate node to turn on the switching transistor SWT regardless of the interval. Also, the gate driver 120 may supply the second voltage Vgh2 to the gate node to turn on the sensing transistor SENT regardless of the interval.

In this structure, the sensing transistor SENT may be turned on in a saturation region to increase turn-on resistance, and the switching transistor SWT may be turned on in a linear region to decrease turn-on resistance.

In this structure, the turn-on resistance of the sensing transistor SENT may be greater than that of the switching transistor SWT.

The power management unit may separately generate the first voltage Vgh1 and the second voltage Vgh2 simultaneously and supply them to the gate driver 120 .

9 is a diagram showing a fourth example of a circuit configuration of a power management unit.

Referring to FIG. 9 , the power management unit 950 may include a first boost circuit BC1 generating the first voltage Vgh1 and a second boost circuit BC2 generating the second voltage Vgh2. .

Also, the power management unit 950 may supply the first voltage Vgh1 to the gate node of the switching transistor SWT through the gate driver 120 . Also, the power management unit 950 may supply the second voltage Vgh2 to the gate node of the sensing transistor SENT through the gate driver 120 .

Meanwhile, the power management unit may generate the turn-on voltage Vgh using a circuit other than the boost circuit. For example, the power management unit may generate the turn-on voltage Vgh using a low dropout (LDO) regulator or may generate the turn-on voltage Vgh using a buck type circuit.

In the above, one embodiment of the present invention has been described. According to this embodiment, the influence of noise can be reduced when the organic light emitting display device senses characteristic values of pixels. Specifically, the organic light emitting display can reduce noise transmitted through the sensing line by increasing the turn-on resistance of the sensing transistor.

Terms such as "comprise", "comprise" or "have" described above mean that the corresponding component may be inherent unless otherwise stated, and therefore do not exclude other components. It should be construed that it may further include other components. All terms, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs, unless defined otherwise. Commonly used terms, such as terms defined in a dictionary, should be interpreted as consistent with the meaning in the context of the related art, and unless explicitly defined in the present invention, they are not interpreted in an ideal or excessively formal meaning.

The above description is merely an example of the technical idea of the present invention, and various modifications and variations can be made to those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed according to the claims below, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

Claims (10)

An organic light emitting diode, a driving transistor for driving the organic light emitting diode, a switching transistor positioned between a gate node of the driving transistor and a data line, and a sensing transistor positioned between a source node or drain node of the driving transistor and a sensing line. a display panel on which a plurality of pixels are disposed; and
A gate driver supplying a first voltage to the gate node of the switching transistor and the sensing transistor in a display driving section and supplying a second voltage different from the first voltage to the gate node of the switching transistor and the sensing transistor in a display sensing section. including,
A display device wherein a turn-on resistance (rds-on) of the sensing transistor is further increased when the second voltage is supplied compared to the first voltage. According to claim 1,
In the display driving period, the switching transistor is turned on in a linear region,
In the display sensing period, the sensing transistor is turned on in a saturation region. delete According to claim 1,
Further comprising a power management unit and a timing controller,
The power management unit changes the voltage supplied to the sensing transistor from the first voltage to the second voltage according to control information received from the timing controller. According to claim 1,
Further comprising a power management unit for selectively generating the first voltage and the second voltage,
The power management unit,
A display device that performs feedback control using a voltage divider circuit that senses an output voltage, and changes the first voltage to the second voltage by changing an impedance of the voltage divider circuit. According to claim 1,
Further comprising a power management unit for generating the first voltage and the second voltage at the same time,
The power management unit,
A display device supplying one of the first voltage and the second voltage to a gate node of the sensing transistor using a selection circuit. An organic light emitting diode, a driving transistor for driving the organic light emitting diode, a switching transistor positioned between a gate node of the driving transistor and a data line, and a sensing transistor positioned between a source node or drain node of the driving transistor and a sensing line. a display panel on which a plurality of pixels are disposed; and
a gate driver supplying a first voltage to a gate node of the switching transistor and a second voltage different from the first voltage to a gate node of the sensing transistor;
A display device wherein a turn-on resistance (rds-on) of the sensing transistor is further increased when the second voltage is supplied compared to the first voltage. According to claim 7,
The display device of claim 1 , wherein the sensing transistor is turned on in a saturation region and the switching transistor is turned on in a linear region. According to claim 7,
The turn-on resistance (rds-on) of the sensing transistor is greater than the turn-on resistance of the switching transistor. According to claim 7,
Further comprising a power management unit for generating the first voltage and the second voltage at the same time,
The power management unit supplies the first voltage to a gate node of the switching transistor and the second voltage to a gate node of the sensing transistor through the gate driver.

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