A controller for a display panel may include a first supply circuit to output first and second driving voltages to a sub-pixel of a first color; and a second supply circuit to output third and fourth driving voltages to a sub-pixel of a second color. The first driving voltage may be greater than the second driving voltage, and the third driving voltage may be greater than the fourth driving voltage. Also, at least three of the first, second, third, and fourth driving voltages may be different from one another.