Display device and method driving the same

1. A display device comprising:

a timing controller configured to derive data signals for a display panel from external signals;

a date driver configured to derive data voltages from the data signals and apply the data voltages to data lines on the display panel;

a gamma IC (integrated circuit) chip configured to apply gamma voltages to the data driver;

a power supply IC chip configured to apply a most significant voltage to the data driver;

a DAC (digital-to-analog converter) configured to receive the gamma voltages and the most significant voltage from the gamma IC chip and the power supply IC chip, respectively, and generate the data voltages corresponding to the data signals; and

a power supply unit configured to convert the gamma voltages and the most significant voltage using the data signals and apply the converted gamma voltages and the converted most significant voltage to the DAC;

wherein the power supply unit includes an extraction portion configured to extract a maximum gray level, a minimum gray level, and unused middle gray levels of the data signals; and

wherein the powers supply unit further includes a voltage converter configured to convert the calculated gamma voltages and the calculated most significant voltage, and

wherein the voltage converter enables the gamma reference voltages corresponding to the unused middle gray levels to be adjusted to be at least one of gamma reference voltages corresponding to the maximum gray level and gamma reference voltages corresponding to the minimum gray level.

2. The display device of claim 1 , wherein the power supply unit further includes:

an arithmetic portion configured to calculate the gamma voltages and the most significant voltage using the data signals.

3. The display device of claim 2 , wherein the display device further includes a frame memory configured to store a single frame of the data signals.

4. The display device of claim 2 , wherein the extraction portion extracts red data signals, green data signals and blue data signals.

5. The display device of claim 1 , wherein the voltage converter converts the most significant voltage into a voltage value corresponding to the maximum gray level.

6. The display device of claim 4 , wherein the gamma reference voltages for at least one of the red, green and blue data signals are adjusted to be either a ground voltage or a voltage corresponding to the maximum gray level.

7. The display device of claim 1 , wherein the gamma IC chip is a programmable gamma IC chip capable of being reprogrammed.

8. The display device of claim 1 , wherein the DAC is included in the data driver.

9. A method of driving a display device, the method comprising:

storing data signals applied from a timing controller;

extracting the data signals;

calculating output voltage values based on the data signals;

adjusting output voltages of a power supply IC chip and a gamma IC chip to be the calculated output voltage values; and

outputting the stored data signals to a display panel using the adjusted output voltages;

wherein extracting the data signal comprises extracting a maximum gray level, a minimum gray level, and unused middle gray levels of the data signals; and

wherein adjusting the output voltages comprises adjusting gamma reference voltages corresponding to the unused middle gray levels to at least one of gamma reference voltages corresponding to the maximum gray level and gamma reference voltages corresponding to the minimum gray level.

10. The method of claim 9 , wherein the extraction of the data signals comprises extracting red data signals, green data signals and blue data signals.

11. The method of claim 9 , wherein the adjustment of the output voltages comprises adjusting a most significant voltage of the power supply IC chip to a voltage value corresponding to the maximum gray level.

12. The method of claim 10 , wherein gamma reference voltages for at least one of the red, green and blue data signals are adjusted to be either a ground voltage or a voltage corresponding to the maximum gray level.