An organic light-emitting diode (OLED) display panel includes a plurality of pixels displaying a plurality of colors. Each pixel has an OLED element. A gamma voltage-generating section generates a reference gamma voltage based on a gamma curve in which the lowest gradation of the total number of gradations is mapped as a negative data voltage with respect to a reference voltage. A data conversion section converts a first data signal into a second data signal that includes data corresponding to the lowest gradation. A source drive section converts the second data signal into a third data signal by using the reference gamma voltage to provide the OLED display panel with the third data signal.