KR102614098B1 - Voltage compensation circuit and display device including the same - Google Patents

Abstract

A voltage compensation circuit is provided that can compensate for low temperature by outputting a gate high voltage that is changed to an optimal level according to the surrounding temperature. The voltage compensation circuit generates a compensation value from one of a plurality of internally stored feedback voltages in a low-temperature operating environment of the display device, increases the level of the gate high voltage, and outputs the compensation value.

Description

Voltage compensation circuit and display device including the same}

The present invention relates to a voltage compensation circuit capable of compensating for low temperatures of a display device by outputting a gate high voltage varied at an optimal level depending on the ambient temperature, and a display device including the same.

Liquid crystal display (LCD), a representative display device of flat panel displays, is a device that displays images using the optical anisotropy of liquid crystal, and has advantages such as thinness, small size, low power consumption, and high image quality.

The liquid crystal display device includes a liquid crystal panel, a backlight unit, and driving circuits that drive them. A liquid crystal panel is composed of a liquid crystal layer sandwiched between two substrates. The backlight unit provides light to the liquid crystal panel from the bottom of the liquid crystal panel. The driving circuits generate and output driving signals to drive the liquid crystal panel and the backlight unit. Among the driving circuits, except for the circuits directly connected to the liquid crystal panel, such as the gate driving circuit and the data driving circuit, the remaining circuits are formed in the form of chips on a printed circuit board.

In the above-mentioned liquid crystal display device, as the surrounding temperature decreases, the level of the gate signal supplied to each pixel of the liquid crystal panel decreases. This decrease in the level of the gate signal causes charging failure in each pixel of the liquid crystal panel. Accordingly, the conventional liquid crystal display device includes a temperature compensation circuit that varies the level of the gate high voltage according to the surrounding temperature and outputs it to the gate driving circuit. The temperature compensation circuit outputs a high-level gate high voltage in the low-temperature operating environment of the liquid crystal display device.

1 is a diagram showing a conventional temperature compensation circuit.

As shown in FIG. 1, the conventional temperature compensation circuit 10 includes a voltage regulator 11, a low temperature compensation unit 13, and a temperature detection unit 15. Here, the voltage regulator 11 and the low temperature compensation unit 13 are composed of an integrated circuit (IC) on a printed circuit board (not shown) of the liquid crystal display device, and the temperature detection unit 15 is the integrated circuit. It is placed adjacent to .

The temperature detection unit 15 detects the surrounding temperature and compares it with the reference temperature, then changes the resistance value (△R) according to the comparison result and outputs it to the low temperature compensation unit 13. The temperature sensing unit 15 outputs a high level resistance value (△R) to the low temperature compensation unit 13 as the surrounding temperature is lower than the reference temperature. The temperature sensing unit 15 is composed of a temperature sensing element such as a thermistor resistor.

The low-temperature compensation unit 13 receives the gate high voltage (VGH) output from the voltage regulator 11 as feedback (F_VGH), and receives a compensation value (△V) according to the resistance value (△R) provided from the temperature detection unit 15. ) is calculated. The compensation value (ΔV) is output to the voltage regulator 11.

The voltage regulator 11 generates and outputs a gate high voltage (VGH) from an externally input voltage (VDD), and generates and outputs a gate high voltage (VGH) according to the compensation value (△V) output from the low temperature compensation unit 13. ) varies the level. The voltage regulator 11 outputs a gate high voltage (VGH) whose level has been changed to the gate driving circuit.

Figure 2 is a diagram showing the operation of a conventional temperature compensation circuit.

As described above, the conventional temperature compensation circuit 10 generates a compensation value (△V) according to the resistance value (△R) output from the temperature sensing unit 15, and matches the generated compensation value (△V) with The level of the gate high voltage (VGH) is varied accordingly.

At this time, as shown in FIG. 2, the temperature compensation circuit 10 generates and outputs the initial gate high voltage (VGH') in the initial operation of the liquid crystal display device, and gradually reduces it for a certain period of time (△t1) to reach the target. Outputs gate high voltage (VGH).

In other words, when the liquid crystal display device is first powered on in a low temperature operating environment, the temperature compensation circuit 10 sets the target gate high voltage (VGH), that is, the gate high for low temperature compensation, for a certain period of time (△t1). The initial gate high voltage (VGH') at a level greater than the voltage is output. At this time, the predetermined time (△t1) during which the temperature compensation circuit 10 first outputs the gate high voltage (VGH') may be approximately 1 minute or more.

That is, in the conventional liquid crystal display device, a voltage level higher than the target gate high voltage is output from the temperature compensation circuit 10 for a certain period of time (△t1) during the initial operation, so a high level gate signal is applied to the liquid crystal panel. . Therefore, image quality defects such as spots and horizontal crosstalk occur in the displayed image in the liquid crystal panel of the conventional liquid crystal display device.

The object of the present invention is to provide a voltage compensation circuit capable of compensating for low temperatures of a display device by outputting a gate high voltage varied at an optimal level depending on the ambient temperature, and a display device including the same.

The voltage compensation circuit of the present invention for achieving the above object outputs a gate high voltage varied to an optimal level according to the ambient temperature of the display device. For this purpose, the voltage compensation circuit includes a determination unit, a first feedback unit, a second feedback unit, a selection unit, a comparison unit, and a voltage adjustment unit.

The determination unit outputs a control code and selection signal according to the resistance value that varies depending on the surrounding temperature.

The first feedback unit outputs a first feedback voltage from the gate high voltage, and the second feedback unit outputs a second feedback voltage corresponding to the control code output from the determination unit. In the second feedback unit, a plurality of feedback voltages corresponding to each control code in a one-to-one correspondence are stored, and one feedback voltage corresponding to the control code output from the determination unit is output as the second feedback voltage.

The selection unit outputs one of the first feedback voltage and the second feedback voltage in response to the selection signal output from the determination unit.

The comparison unit generates a compensation value according to the feedback voltage output from the selection unit.

The voltage regulator changes and outputs the level of the gate high voltage according to the compensation value output from the comparison unit.

The voltage compensation circuit according to the present invention can output a gate high voltage compensated to an accurate level to the gate driver in a low-temperature operating environment of a display device. Accordingly, it is possible to prevent image quality defects from occurring in the displayed image of the display panel.

Additionally, the voltage compensation circuit can output a gate high voltage with an optimal level in a low-temperature operating environment for each of various models of display devices. Therefore, there is no need to set the reference temperature of the temperature sensing unit for each model of the display device, thereby simplifying the manufacturing process of the display device.

1 is a diagram showing a conventional temperature compensation circuit.
Figure 2 is a diagram showing the operation of a conventional temperature compensation circuit.
Figure 3 is a diagram showing a display device according to an embodiment of the present invention.
FIG. 4 is a diagram showing the configuration of the voltage compensation circuit of FIG. 3.
FIG. 5 is a diagram showing an example of the second feedback unit of FIG. 4.
Figure 6 is a diagram showing the operation of the voltage compensation circuit of the present invention.

Hereinafter, a voltage compensation circuit according to the present invention and a display device including the same will be described in detail with reference to the attached drawings. For convenience of explanation, the display device of this embodiment is described as an example of a liquid crystal display device, but the present invention is not limited thereto. The display device of the present invention may be one of various flat panel displays, such as a plasma display panel, a field emission display device, and an organic light emitting display device, in addition to a liquid crystal display device.

Figure 3 is a diagram showing a display device according to an embodiment of the present invention.

Referring to FIG. 3, the display device 100 of this embodiment may include a display panel 110 and a plurality of driving circuits that drive the display panel 110. The driving circuits may include a gate driver 120, a data driver 130, a timing control unit 140, and a voltage supply unit 150.

The display panel 110 may be a liquid crystal panel including an array substrate (not shown), a color filter substrate (not shown), and a liquid crystal layer (not shown) interposed between the two substrates. The display panel 101 may include a plurality of gate lines (GL) and a plurality of data lines (DL) that cross each other to define a pixel area. A pixel (P) including a thin film transistor (T) and a liquid crystal cell (LC) may be formed in each pixel area.

The thin film transistor (T) of each pixel (P) has a gate electrode connected to the gate line (GL), a source electrode connected to the data line (DL), and a drain electrode connected to one end of the liquid crystal cell (LC). One end of the liquid crystal cell (LC) is connected to the drain electrode of the thin film transistor (T), and the common voltage (VCOM) is applied to the other end.

The thin film transistor (T) is turned on by a gate signal applied through the gate line (GL), and transmits the pixel voltage applied through the data line (DL) to the liquid crystal cell (LC). The liquid crystal cell (LC) charges the pixel voltage transmitted from the thin film transistor (T) and maintains the charged pixel voltage until the next frame of the display panel 101. In addition, the liquid crystal cell (LC) displays an image by adjusting the light transmittance by changing the arrangement of the liquid crystal according to the electric field formed by the charged pixel voltage and the common voltage applied to the other end.

The gate driver 120 may generate a gate signal in response to the gate control signal (GCS) provided from the timing control unit 140. The gate driver 120 may generate a gate signal from the gate high voltage (VGH) and the gate low voltage (VGL) provided by the voltage supply unit 150. The gate signal may be sequentially output to a plurality of gate lines GL of the display panel 110. The gate driver 120 may be configured in the form of a Chip On Film (COF) on one side of the display panel 110 or in the form of a Gate In Panel (GIP) within the display panel 110. Here, the gate high voltage (VGH) provided from the voltage supply unit 150 to the gate driver 120 may be a voltage whose level is varied by the voltage compensation circuit 160.

The data driver 130 may generate a data signal, that is, a pixel voltage, from the image data DATA in response to the data control signal DCS provided from the timing control unit 140. Data signals may be simultaneously output to multiple data lines DL of the display panel 110.

Meanwhile, although not shown in the drawing, the display device 100 may further include a gamma voltage generator (not shown). The gamma voltage generator may generate a gamma voltage of positive polarity (+) or negative polarity (-) and output it to the data driver 130. The data driver 130 selects a gamma voltage of positive polarity (+) or negative polarity (-) corresponding to the gray level of the image data (DATA) according to the polarity control signal (POL) of the data control signal (DCS), The selected gamma voltage can be output as a data signal to each data line (DL).

The timing control unit 140 may generate a gate control signal (GCS) and a data control signal (DCS) from a timing signal (TS) provided from an external system (not shown). The gate control signal (GCS) may be output to the gate driver 120, and the data control signal (DCS) may be output to the data driver 130.

The timing signal (TS) may include a clock signal (DCLK), a data enable signal (DE), a horizontal synchronization signal (Hsync), and a vertical synchronization signal (Vsync). The gate control signal (GCS) may include a gate start pulse signal (GSP), a gate shift clock (GSC), and a gate output enable signal (GOE). The data control signal (DCS) may include a source start pulse signal (SSP), source shift clock (SSC), source output enable signal (SOE), and polarity control signal (POL).

Additionally, the timing control unit 140 may generate image data (DATA) by sorting image signals (RGB) input from an external system according to the resolution of the display panel 110. Image data (DATA) may be output to the data driver 130 together with the data control signal (DCS).

The voltage supply unit 150 may generate and output a plurality of driving voltages, such as gate high voltage (VGH), gate low voltage (VGL), and common voltage (VCOM), from a voltage input from an external system.

The voltage supply unit 150 may output a gate high voltage (VGH) and a gate low voltage (VGL) to the gate driver 120. The voltage supply unit 150 may output a common voltage (VCOM) to the common electrode of the display panel 110.

In addition, the voltage supply unit 150 controls the gate high voltage (VGH) in order to prevent the level of the gate high voltage (VGH) output to the gate driver 120 from decreasing in the low-temperature operating environment of the display device 100. It may further include a voltage compensation circuit 160 that outputs a variable level.

The voltage compensation circuit 160 can compensate for the low-temperature operation of the display device 100 by outputting a high-level gate high voltage (VGH) in a low-temperature operating environment. Additionally, the voltage compensation circuit 160 can output a normal gate high voltage (VGH) in a room temperature operating environment. Here, the gate high voltage (VGH) output in a low temperature operating environment may have a higher level than the gate high voltage (VGH) output in a room temperature operating environment.

FIG. 4 is a diagram showing the configuration of the voltage compensation circuit of FIG. 3.

3 and 4, the voltage compensation circuit 160 of this embodiment increases the level of the gate high voltage (VGH) and outputs it in a low-temperature operating environment of the display device 100. Normal gate high voltage (VGH) can be output in a room temperature operating environment.

For this purpose, the voltage compensation circuit 160 includes feedback units 161 and 164, a temperature detection unit 162, a determination unit 163, a selection unit 165, a comparison unit 166, and a voltage adjustment unit 167. It can be included. The feedback units 161 and 164 may include a first feedback unit 161 and a second feedback unit 164.

The first feedback unit 161 may include a first resistor (R1) and a second resistor (R2). One side of the first resistor (R1) may be connected in parallel to the output terminal of the voltage regulator 167, and the other side may be connected in series to one side of the second resistor (R2). The other side of the second resistor R2 may be connected to ground (GND). The first feedback unit 161 may output the first feedback voltage FB1 by dividing the gate high voltage VGH according to the resistance ratio of the first resistor R1 and the second resistor R2.

The second feedback unit 164 may be configured as a look-up table (LUT) in which a plurality of second feedback voltages FB2 are stored. As shown in FIG. 5, a plurality of control codes (Code) and a plurality of second feedback voltages (FB2) corresponding to them in a one-to-one manner may be stored in the second feedback unit 164. The plurality of second feedback voltages FB2 stored in the second feedback unit 164 may be voltages corresponding to various models of the display device 100. The plurality of second feedback voltages FB2 may have different levels.

The first feedback voltage FB1 output from the first feedback unit 161 may be a voltage corresponding to room temperature operation of the display device 100, and the second feedback voltage FB2 stored in the second feedback unit 164 may be a voltage corresponding to low temperature driving of the display device 100. Additionally, the first feedback voltage FB1 may have a level greater than the second feedback voltage FB2.

The temperature detection unit 162 can detect the ambient temperature of the display device 100 and output a resistance value (Rc) accordingly. The temperature sensing unit 162 may be composed of an element such as a thermistor resistor. The temperature sensing unit 162 may output a resistance value (Rc) whose level increases as the detected ambient temperature becomes lower than the reference temperature, for example, room temperature.

The temperature detection unit 162 includes other components of the voltage compensation circuit 160, namely feedback units 161 and 164, determination unit 163, selection unit 165, comparison unit 166, and voltage adjustment unit ( 167) and can be placed separately from the other.

In other words, each component of the voltage compensation circuit 160, excluding the temperature sensing unit 162, may be disposed within the voltage supply unit 150 composed of one integrated circuit. However, the temperature sensing unit 162 may be placed away from the voltage supply unit 150 for accurate detection of the surrounding temperature, for example, placed at the outermost edge of the printed circuit board (not shown) on which the voltage supply unit 150 is mounted. It can be. Additionally, the temperature sensing unit 162 may be placed on the outside of the display panel 110.

The determination unit 163 may output a control code (Code) and a selection signal (SEL) according to the resistance value (Rc) output from the temperature detection unit 162. The determination unit 163 may compare the resistance value Rc with a reference value and output a control code (Code) and a selection signal (SEL) according to the results.

For example, if the resistance value (Rc) output from the temperature sensing unit 162 is at a level greater than the reference value, the determination unit 163 generates a control code (Code) and a first level, for example, low level selection signal (SEL). ) can be output. In addition, if the resistance value (Rc) output from the temperature sensing unit 162 is at a level lower than the reference value, the determination unit 163 may output only the selection signal (SEL) of the second level, for example, a high level. . Here, the reference value may be the resistance value of the first feedback unit 161.

The second feedback unit 164 described above provides one control code (Code) corresponding to the control code (Code) output from the determination unit 163 among a plurality of pre-stored control codes (Code). 2Feedback voltage (FB2) can be selected and output.

The selection unit 165 may output one of the first feedback voltage FB1 and the second feedback voltage FB2 according to the selection signal SEL output from the determination unit 163.

For example, when the selection signal SEL of the first level is output from the determination unit 163, the selection unit 165 may output the second feedback voltage FB2 output from the second feedback unit 164. Additionally, when the second level selection signal SEL is output from the determination unit 163, the selection unit 165 may output the first feedback voltage FB1 output from the first feedback unit 161.

The comparison unit 166 compares the first feedback voltage (FB1) or the second feedback voltage (FB2) output from the selection unit 165 with the reference voltage (Ref), and sets a compensation value (△V) according to the result. Can be printed. The compensation value ΔV may include a first compensation value and a second compensation value at different levels.

For example, the comparison unit 166 may compare the first feedback voltage FB1 and the reference voltage Ref and output a first compensation value accordingly. Additionally, the comparison unit 166 may compare the second feedback voltage FB2 and the reference voltage Ref and output a second compensation value accordingly. Here, the first compensation value may be at a level smaller than the second compensation value. The reference voltage (Ref) can be input in the form of a triangle wave, square wave, etc.

The voltage adjusting unit 167 may vary and output the level of the gate high voltage (VGH) generated from the power supply voltage (VDD) according to the compensation value (△V) output from the comparing unit 166.

As described above, the voltage compensation circuit 160 can select one of a plurality of voltages previously stored according to the resistance value (Rc) output from the temperature sensing unit 162 and output it as the second feedback voltage (FB2). . Therefore, the voltage compensation circuit 160 of this embodiment can output an accurate compensation voltage, that is, a compensation value (△V), according to the surrounding temperature of the display device 100, thereby improving the operation reliability of the display device 100. there is.

In addition, the voltage compensation circuit 160 of this embodiment stores the second feedback voltage FB2 corresponding to various models of the display device 100, so the temperature detection unit 162 is adjusted for each model of the display device 100. There is no need to set a standard temperature. Accordingly, the manufacturing process of the display device 100 can be simplified.

Hereinafter, the operation of the voltage compensation circuit 160 described above will be described in detail with reference to the drawings.

Figure 6 is a diagram showing the operation of the voltage compensation circuit of the present invention.

Referring to FIGS. 4 and 6, when the display device 100 is powered on, the temperature sensing unit 162 of the voltage compensation circuit 160 can detect the surrounding temperature and output a resistance value (Rc) accordingly. there is. And, the first feedback unit 161 divides the gate high voltage (VGH) output from the voltage regulator 167 according to the first resistor (R1) and the second resistor (R2) to generate a first feedback voltage (FB1). ) can be output.

Meanwhile, during the initial operation of the display device 100, that is, during the time T0 to T1, the ambient temperature is lower than room temperature, so the temperature sensing unit 162 can output a high level resistance value Rc. The resistance value (Rc) may be output at a level that gradually decreases during time T0 to T1.

The determination unit 163 may compare the level of the resistance value Rc output from the temperature sensing unit 162 with a reference value, that is, the resistance value R12 of the first feedback unit 161. Next, the determination unit 163 may output a control code (Code) and a selection signal (SEL) according to the comparison result. Here, the resistance value (R12) of the first feedback unit 161 may be a fixed value based on the first resistance (R1) and the second resistance (R2).

Specifically, during the T0 to T1 operation of the display device 100, the resistance value (Rc) output from the temperature sensing unit 162 has a level greater than the reference value (R12). Accordingly, the determination unit 163 can output a control code (Code) and a first level selection signal (SEL).

Next, the second feedback unit 164 selects and outputs one second feedback voltage (FB2) corresponding to the control code (Code) output from the determination unit 163 among the plurality of stored second feedback voltages (FB2). can do. The selection unit 165 selects one second feedback voltage (FB2) output from the second feedback unit 164 according to the first level selection signal (SEL) output from the determination unit 163 to the comparison unit 166. It can be output as .

Subsequently, the comparison unit 166 may compare the second feedback voltage FB2 with the reference voltage Ref and output a compensation value ΔV corresponding thereto, for example, a second compensation value. Next, the voltage regulator 167 may increase the level of the gate high voltage (VGH) according to the second compensation value and output the gate high voltage in a low temperature environment, that is, the second gate high voltage (VGH2).

Here, the second gate high voltage (VGH2) may be one of the levels of 20 to 30V. In addition, the second gate high voltage (VGH2) is generated from one of the plurality of second feedback voltages (FB2) optimized for each of the various models of the display device 100, so it is optimized for the display device 100 of the corresponding model. It may be a gate high voltage in a low temperature environment.

In this way, the voltage compensation circuit 160 generates the second gate high voltage (VGH) from one of the plurality of second feedback voltages (FB2) optimized in a low temperature environment for each of the various models of the display device 100. Can be printed.

Therefore, the voltage compensation circuit 160 of this embodiment can output a correct level of compensation voltage, that is, the second gate high voltage (VGH), to the gate driver 120 of the display device 100 in a low temperature environment, and accordingly, It is possible to prevent image quality defects from occurring in the displayed image of the display panel 110.

In addition, the voltage compensation circuit 160 of this embodiment can output a second gate high voltage (VGH) optimized for each of the various models of the display device 100, so compared to the prior art, the voltage compensation circuit 160 of the display device 100 There is no need to set the reference temperature of the temperature sensing unit 162 for each model, and thus the manufacturing process of the display device 100 can be simplified.

Meanwhile, during operation of the display device 100 after time T1, the resistance value Rc output from the temperature sensing unit 162 has a level smaller than the reference value R12. Accordingly, the determination unit 163 can output only the second level selection signal (SEL).

The selection unit 165 may output the first feedback voltage FB1 output from the first feedback unit 161 to the comparison unit 166 according to the second level selection signal SEL. Additionally, the comparison unit 166 may compare the first feedback voltage FB1 and the reference voltage Ref and output a first compensation value accordingly. At this time, the second feedback unit 164 does not operate.

Here, the first feedback voltage FB1 output from the first feedback unit 161 has a higher level than the second feedback voltage FB2 previously output from the second feedback unit 164. Additionally, the first compensation value generated by the first feedback voltage FB1 has a lower level than the second compensation value generated by the second feedback voltage FB2.

Subsequently, the voltage regulator 167 may output the first gate high voltage VGH1 in a normal environment, that is, a room temperature environment, according to the first compensation value output from the comparison unit 166. The first gate high voltage (VGH1) may be one of the levels of 10 to 20V.

As described above, the voltage compensation circuit 160 of this embodiment has an increased level from one of the plurality of feedback voltages stored in the second feedback unit 164 according to the operation of the temperature detection unit 162 in a low temperature environment. A gate high voltage can be generated and output. At this time, the plurality of stored feedback voltages may be voltages optimized for a low-temperature environment for each of the plurality of models of the display device 100.

Therefore, compared to a conventional voltage compensation circuit, the voltage compensation circuit 160 of this embodiment can output a gate high voltage compensated to an accurate level in a low-temperature operating environment of the display device 100. Therefore, in the display device 100 of the present invention, it is possible to prevent image quality defects from occurring in the display panel 110.

Additionally, the voltage compensation circuit 160 of this embodiment does not need to set the reference temperature inside the temperature sensing unit 162 for each of the multiple models of the display device 100. Therefore, compared to a conventional display device, the display device 100 of the present invention can perform accurate low-temperature compensation using a gate high voltage having an optimal level for each of multiple models.

Although many details are described in detail in the foregoing description, this should be interpreted as an example of a preferred embodiment rather than limiting the scope of the invention. Therefore, the invention should not be determined by the described embodiments, but by the scope of the patent claims and their equivalents.

100: display device 110: display panel
120: gate driving part 130: data driving part
140: timing control unit 150: voltage supply unit
160: voltage compensation circuit 161, 164: feedback unit
162: temperature detection unit 163: judgment unit
165: selection unit 166: comparison unit
167: Voltage regulator

Claims (10)

a determination unit that outputs a control code and a selection signal according to a resistance value that varies depending on the ambient temperature;
a first feedback unit that outputs a first feedback voltage from the gate high voltage;
a second feedback unit that outputs one of the plurality of stored feedback voltages corresponding to the control code as a second feedback voltage;
a selection unit outputting one of the first feedback voltage and the second feedback voltage in response to the selection signal;
a comparison unit that generates a compensation value from the output of the selection unit; and
A voltage compensation circuit including a voltage regulator that varies the level of the gate high voltage and outputs it according to the compensation value. According to paragraph 1,
The judgment department,
If the level of the resistance value is greater than the reference value, output the control code and a first level selection signal,
A voltage compensation circuit that outputs a second level selection signal when the level of the resistance value is less than the reference value. According to paragraph 2,
The selection part is,
A voltage compensation circuit that outputs the second feedback voltage in response to the first level selection signal and outputs the first feedback voltage in response to the second level selection signal. According to paragraph 2,
A voltage compensation circuit wherein the reference value is the resistance value of the first feedback unit. According to paragraph 1,
A voltage compensation circuit further comprising a temperature detection unit that outputs the resistance value whose level increases as the surrounding temperature becomes lower than the reference temperature. According to paragraph 1,
The comparison section,
A voltage compensation circuit that compares the first feedback voltage and the second feedback voltage with a reference voltage and outputs the compensation value. According to clause 6,
A voltage compensation circuit wherein the compensation value by the first feedback voltage is at a level smaller than the compensation value by the second feedback voltage. According to clause 6,
The voltage regulator,
A voltage compensation circuit that increases and outputs the level of the gate high voltage in response to a compensation value by the second feedback voltage output from the comparison unit. According to paragraph 1,
A voltage compensation circuit wherein the first feedback voltage is at a level greater than the second feedback voltage. A display panel equipped with a plurality of gate lines and a plurality of data lines;
a gate driver sequentially outputting gate signals to the plurality of gate lines; and
It includes a voltage compensation circuit that generates a gate high voltage with a variable level from the input voltage and outputs it to the gate driver,
The voltage compensation circuit is,
a determination unit that outputs a control code and a selection signal according to a resistance value that varies depending on the ambient temperature;
a first feedback unit outputting a first feedback voltage from the gate high voltage;
a second feedback unit that outputs one of the plurality of stored feedback voltages corresponding to the control code as a second feedback voltage;
a selection unit outputting one of the first feedback voltage and the second feedback voltage in response to the selection signal;
a comparison unit that generates a compensation value from the output of the selection unit; and
A display device comprising a voltage regulator that varies the level of the gate high voltage and outputs the gate high voltage according to the compensation value.