Display device and driving method thereof

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

• determining an image pattern of an image based on an input image signal;
• generating a control signal controlling levels of a first quarter power voltage (QHAVDD) and a second quarter power voltage (QLAVDD) based on the determined image pattern, the first quarter power voltage having a level between a power voltage (AVDD) and a half power voltage (HAVDD), the second quarter power voltage having a level between the half power voltage and a ground voltage;
• generating the first quarter power voltage and the second quarter power voltage based on the control signal;
• and
• alternately outputting, by a data driver, the first quarter power voltage or the second quarter power voltage and a data voltage to the data line.

A display device, comprising:

• a display panel;
• a driving voltage generator configured to generate a power voltage, a half power voltage, a first quarter power voltage, and a second quarter power voltage, the first quarter power voltage having a level between the power voltage and the half power voltage, the second quarter power voltage having a level between the half power voltage and a ground voltage;
• a gray voltage generator configured to generate a data voltage from the power voltage and the half power voltage;
• a data driver configured to alternately output the first quarter power voltage or the second quarter power voltage and the data voltage to the display panel;
• and
• a signal controller configured to determine an image pattern of an image from an external circuit and configured to control the driving voltage generator to adjust the levels of the first quarter power voltage and the second quarter power voltage, depending on the determined image pattern.