Display device and method of driving the same

1. A display device comprising:

pulse-amplitude modulation (PAM) data lines to which PAM data voltages are respectively applied;

pulse-width modulation (PWM) data lines to which PWM data voltages are respectively applied; and

a plurality of sub-pixels respectively connected to the PWM data lines and the PAM data lines,

wherein a sub-pixel among the plurality of sub-pixels comprises:

a light emitting element;

a first pixel driver configured to supply a control current according to one of the PWM data voltages to a first node;

a second pixel driver configured to generate a driving current according to one of the PAM data voltages; and

a third pixel driver configured to adjust a period during which the driving current is supplied to the light emitting element according to a voltage of the first node,

wherein a peak current value of the driving current when the sub-pixel emits a light corresponding to a low gray level region is smaller than a peak current value of the driving current when the sub-pixel emits a light corresponding to a high gray level region higher than the low gray level region.

2. The display device of claim 1 , wherein the low gray level region is a black gray level region, and the high gray level region includes a gray level region and a white gray level region.

3. The display device of claim 1 , wherein the one PWM data voltage rises from a first low gray level voltage to a second low gray level voltage in the low gray level region, and rises from a first high gray level voltage to a second high gray level voltage in the high gray level region.

4. The display device of claim 3 , wherein the second low gray level voltage is greater than the first low gray level voltage.

5. The display device of claim 1 , wherein the one PAM data voltage has a high PAM data voltage in the low gray level region and has a low PAM data voltage lower than the high PAM data voltage in the high gray level region.

6. A display device comprising:

a display panel comprising pulse-amplitude modulation (PAM) data lines, pulse-width modulation (PWM) data lines, and a plurality of sub-pixels respectively connected to the PWM data lines and the PAM data lines;

a source driver configured to apply PWM data voltages to the PWM data lines;

a power supply unit configured to apply PAM data voltages to the PAM data lines; and

a digital data converter configured to determine digital video data corresponding to a low gray level region among digital video data, and increase a value of the digital video data corresponding to the low gray level region to output converted digital data.

7. The display device of claim 6 , further comprising a timing controller configured to receive the converted digital data from the digital data converter and output the converted digital data and a source control signal to the source driver,

wherein the source driver converts the converted digital data into the PWM data voltages.

8. The display device of claim 6 , wherein the power supply unit outputs a high PAM data voltage and a low PAM data voltage to each of the PAM data lines according to a PAM control signal inputted from the digital data converter.

9. The display device of claim 8 , wherein the high PAM data voltage has a level higher than that of the low PAM data voltage.

10. The display device of claim 8 , wherein the power supply unit outputs the high PAM data voltage to a first PAM data line among the PAM data lines in response to a first PAM control signal of a first level voltage, and outputs the low PAM data voltage to the first PAM data line in response to the first PAM control signal of a second level voltage.

11. The display device of claim 8 , wherein the digital data converter outputs a PAM control signal corresponding to the low gray level region as the first level voltage, and outputs a PAM control signal corresponding to the high gray level region as the second level voltage.

12. The display device of claim 6 , wherein the low gray level region is a black gray level region, and the high gray level region includes a gray level region and a white gray level region.

13. The display device of claim 6 , wherein a peak current value of a driving current when one of the sub-pixels emits a light corresponding to a low gray level region is smaller than a peak current value of the driving current when the one sub-pixel emits a light corresponding to a high gray level region higher than the low gray level region.

14. The display device of claim 6 , wherein the PWM data voltage rises from a first low gray level voltage to a second low gray level voltage in the low gray level region, and rises from a first high gray level voltage to a second high gray level voltage in the high gray level region.

15. The display device of claim 14 , wherein the second low gray level voltage is greater than the first low gray level voltage.

16. A method of driving a display device, comprising:

determining digital video data corresponding to a low gray level region among digital video data;

outputting modulated digital data by increasing a value of the digital video data of the low gray level region;

outputting a pulse-width modulation (PAM) control signal corresponding to the low gray level region as a first level voltage and outputting the pulse-width modulation (PAM) control signal corresponding to a high gray level region other than the low gray level region as a second level voltage;

generating PWM data voltages according to the modulated digital video data and outputting the PWM data voltages to PWM data lines; and

outputting PAM data voltages to PAM data lines according to the PAM control signal.

17. The method of claim 16 , wherein the outputting of the PAM data voltages to the PAM data lines according to the PAM control signal comprises:

outputting one of a high PAM data voltage and a low PAM data voltage to each of the PAM data lines according to the PAM control signal.

18. The method of claim 16 , wherein the outputting of the PAM data voltages to the PAM data lines according to the PAM control signal comprises:

outputting the high PAM data voltage to a first PAM data line among the PAM data lines when a first PAM control signal of a first level voltage is inputted, and outputting the low PAM data voltage to the first PAM data line when a first PAM control signal of a second level voltage is inputted.

19. The method of claim 16 , wherein the PWM data voltage rises from a first low gray level voltage to a second low gray level voltage in the low gray level region, and rises from a first high gray level voltage to a second high gray level voltage in the high gray level region.

20. The method of claim 19 , wherein the second low gray level voltage is greater than the first low gray level voltage.

21. A display device comprising a plurality of sub-pixels, each sub-pixel comprising:

a light emitting element;

a first pixel driver configured to supply a control current to a first node according to a pulse-width modulation (PWM) data voltage received from a first data line;

a second pixel driver configured to generate a driving current according to a pulse-amplitude modulation (PAM) data voltage received from a second other data line; and

a third pixel driver configured to adjust a period during which the driving current is supplied to the light emitting element according to a voltage of the first node,

wherein a peak current value of the driving current when the light-emitting element emits light for image data having a gray level between a first level and a second level is smaller than a peak current value of the driving current when the light-emitting element emits light for image data having a gray level region between the second level and a third level higher than the first level.

22. The display device of claim 21 , wherein the first level is 0 and the third level is a maximum gray level supported by the display device.