Display device for adjusting gamma voltage and method for operating the same

1 . A display device, comprising:

a display panel comprising a plurality of pixels;

a driver IC configured to convert digital data corresponding to an input image to an analog voltage using a gamma voltage, and to supply the analog voltage to the plurality of pixels; and

a power supply configured to supply a pixel driving voltage to the display panel and the driver IC,

wherein the driver IC comprises:

a weight selector configured to select a weight for adjusting the gamma voltage based on a change amount of the pixel driving voltage supplied from the power supply; and

a gamma reference voltage generating unit configured to generate a gamma reference voltage based on the selected weight, and

wherein the gamma reference voltage generating unit generates the gamma reference voltage using a reference voltage corresponding to the selected weight, the reference voltage being determined based on a table indicating at least one reference voltage corresponding to the selected weight.

2 . The display device of claim 1 , wherein the gamma reference voltage generating unit comprises:

a weight circuit configured to boost or reduce the pixel driving voltage by a specified multiple based on the selected weight; and

a gamma reference voltage generator configured to generate the gamma reference voltage based on the boosted or reduced pixel driving voltage, a preset offset voltage, and the reference voltage corresponding to the selected weight.

3 . The display device of claim 2 , wherein the weight circuit comprises:

a buffer configured to buffer the preset offset voltage;

a voltage divider circuit configured to divide the pixel driving voltage using a plurality of series-connected resistor elements;

a multiplexer connected to the voltage divider circuit and configured to select one of the divided pixel driving voltage from the voltage divider circuit according to a first control signal generated based on the selected weight and output the selected pixel driving voltage;

a first switch connected between the voltage divider circuit and the gamma reference voltage generator and configured to be turned on or off by a second control signal generated based on the selected weight; and

a second switch connected between the multiplexer and the gamma reference voltage generator and configured to be turned on or off by the second control signal.

4 . The display device of claim 3 , wherein the second control signal selectively turns on one of the first switch and the second switch.

5 . The display device of claim 2 , wherein the gamma reference voltage generator comprises:

a first gamma reference voltage generator configured to generate a first gamma reference voltage based on the boosted or reduced pixel driving voltage, the preset offset voltage and a first reference voltage corresponding to the selected weight; and

a second gamma reference voltage generator configured to generate a second gamma reference voltage based on the boosted or reduced pixel driving voltage, the preset offset voltage and a second reference voltage corresponding to the selected weight.

6 . The display device of claim 5 , wherein the first gamma reference voltage is an upper limit value of the gamma voltage, and

wherein the second gamma reference voltage is a lower limit value of the gamma voltage.

7 . The display device of claim 1 , wherein the weight is determined by a difference between the pixel driving voltage output from the power supply and the pixel driving voltage input to the driver IC.

8 . The display device of claim 1 , wherein the weight is determined by a difference between the pixel driving voltage input to the driver IC and the pixel driving voltage input to the display panel.

9 . The display device of claim 1 , wherein the driver IC further comprises a gamma voltage output unit configured to generate and output the gamma voltage based on the gamma reference voltage.

10 . A method for operating a display device, the method comprising:

selecting a weight for adjusting a gamma voltage of a digital-to-analog converter (DAC) based on a change amount of a pixel driving voltage supplied from a power supply;

generating a gamma reference voltage which is used to generate the gamma voltage based on the selected weight, wherein the gamma reference voltage is generated using a reference voltage corresponding to the selected weight, the reference voltage being determined based on a table indicating at least one reference voltage corresponding to the selected weight; and

adjusting the gamma voltage using the generated gamma reference voltage.

11 . The method of claim 10 , wherein the generating of the gamma reference voltage comprises:

boosting or reducing the pixel driving voltage by a specified multiple based on the selected weight; and

generating the gamma reference voltage based on the boosted or reduced pixel driving voltage, a preset offset voltage, and the reference voltage corresponding to the selected weight.

12 . The method of claim 11 , wherein the pixel driving voltage is boosted or reduced by the specified multiple using a voltage divider circuit comprising a plurality of series-connected resistor elements and configured to divide the pixel driving voltage, and

wherein the voltage divider circuit is connected to a multiplexer.

13 . The method of claim 12 , wherein the multiplexer is configured to operate according to a control signal generated based on the selected weight.

14 . The method of claim 11 , wherein the generating of the gamma reference voltage comprises:

generating a first gamma reference voltage based on the boosted or reduced pixel driving voltage, the preset offset voltage, and a first reference voltage corresponding to the selected weight; and

generating a second gamma reference voltage based on the boosted or reduced pixel driving voltage, the preset offset voltage, and a second reference voltage corresponding to the selected weight.

15 . The method of claim 14 , wherein the first gamma reference voltage is an upper limit value of the gamma voltage, and

wherein the second gamma reference voltage is a lower limit value of the gamma voltage.

16 . The method of claim 10 , wherein the selecting of the weight comprises:

determining the weight based on a difference between the pixel driving voltage output from the power supply and the pixel driving voltage input to a driver IC.

17 . The method of claim 10 , wherein the selecting of the weight comprises:

determining the weight based on a difference between the pixel driving voltage input to a driver IC and the pixel driving voltage input to a display panel.