Display device and driving method thereof

1. A display device comprising:

a display panel including a plurality of pixels;

a power supply configured to generate a gamma power voltage based on a power control signal;

a gamma voltage generator configured to generate gamma voltages based on the gamma power voltage and a gamma control signal;

a data driver configured to generate a data signal corresponding to a grayscale value included in image data using the gamma voltages and to provide the data signal to the pixels; and

a power controller configured to adjust the power control signal and the gamma control signal based on a maximum voltage level of the data signal,

wherein a voltage level of the gamma power voltage is proportional to the maximum voltage level of the data signal.

2. The display device of claim 1 , further comprising:

a storage configured to store a first setting value for the power control signal, second setting values for the gamma control signal, and a lookup table,

wherein the first setting value represents the voltage level of the gamma power voltage,

the second setting values represent a relative position of the gamma voltages with respect to the voltage level of the gamma power voltage,

the lookup table includes a selection value for gray voltage corresponding to the grayscale value among gray voltages, and

the gray voltages are generated by dividing the gamma voltages.

3. The display device of claim 2 , wherein the power controller includes:

a storage block configured to load the first setting value of the power control signal, the second setting values of the gamma control signal, and the lookup table from the storage; and

a power control block configured to calculate the maximum voltage level of the data signal based on the first setting value, the second setting values, and the lookup table, to calculate a target voltage level of the gamma power voltage based on the maximum voltage level of the data signal and a margin setting value, and to update the first setting value of the power control signal and the second setting values of the gamma control signal based on the target voltage level, respectively.

4. The display device of claim 3 , wherein the pixels include a first pixel configured to emit light with a first color, a second pixel configured to emit light with a second color, and a third pixel configured to emit light with a third color, and

the maximum voltage level of the data signal corresponds to the first pixel.

5. The display device of claim 3 , wherein the margin setting value increases as a driving time of the display panel increases.

6. The display device of claim 3 , wherein the power controller is configured to calculate an expected voltage level of the gamma power voltage based on the first setting value, to calculate a first gamma voltage based on the expected voltage level of the gamma power voltage and a first gamma setting value among the second setting values, and to calculate a maximum voltage level of the data signal based on the first gamma voltage and the lookup table, and

wherein the first gamma voltage has a largest voltage level of the gamma voltages.

7. The display device of claim 6 , wherein the first gamma voltage has a voltage level that is greater than the maximum voltage level of the data signal by the margin setting value, and

wherein the margin setting value is in a range of 10% to 15% of the maximum voltage level of the data signal.

8. The display device of claim 7 , wherein the voltage level of the gamma power voltage is greater than the voltage level of the first gamma voltage by the margin setting value.

9. The display device of claim 6 , wherein the selection value of the lookup table is variable.

10. The display device of claim 6 , wherein the maximum voltage level of the data signal corresponds to a maximum grayscale value when a load of the image data is less than or equal to a reference load, and is greater than a voltage level corresponding to the maximum grayscale value when the load of the image data is greater than the reference load.

11. A driving method of a display device, wherein the display device is configured to:

generate gamma voltages based on a gamma power voltage and a gamma control signal;

generate a data signal corresponding to a grayscale value included in image data using the gamma voltages; and

provide the data signal to pixels, the driving method comprising:

extracting a maximum voltage level of the data signal;

determining a target voltage level of the gamma power voltage based on the maximum voltage level; and

adjusting at least one of the gamma voltages by changing the gamma control signal based on the target voltage level of the gamma power voltage,

wherein the target voltage level of the gamma power voltage is proportional to the maximum voltage level of the data signal.

12. The driving method of claim 11 , further comprising:

storing the target voltage level of the gamma power voltage and the changed gamma control signal in a storage.

13. The driving method of claim 12 , wherein a target voltage level of the gamma power voltage is determined based on the maximum voltage level of the data signal and a margin setting value.

14. The driving method of claim 13 , wherein the extracting the maximum voltage level of the data signal includes:

calculating a first gamma voltage having a largest voltage level among the gamma voltages based on the gamma power voltage and a first gamma setting value; and

calculating the maximum voltage level of the data signal based on the first gamma voltage and a predetermined lookup table,

wherein the first gamma setting value represents a relative position of the first gamma voltage with respect to the voltage level of the gamma power voltage,

wherein the lookup table includes a selection value for a gray voltage corresponding to the grayscale value among gray voltages,

wherein the gray voltages are generated by dividing the gamma voltages, and

wherein the target voltage level of the gamma power voltage is calculated by summing the maximum voltage level of the data signal and the margin setting value.

15. The driving method of claim 14 , wherein the maximum voltage level of the data signal corresponds to a maximum grayscale value when a load of the image data is less than or equal to a reference load, and is greater than a voltage level corresponding to the maximum grayscale value when the load of the image data is greater than the reference load.