Abstract: A display device includes a display panel including a plurality of pixels, a power supply configured to generate a power voltage to drive the plurality of pixels and positioned external to the display panel, and a power voltage controller configured to receive the power voltage from the power supply, to generate a divided voltage by dividing the power voltage, to output a compare result signal by comparing the divided voltage to a predetermined reference voltage, and to control an output of the power supply to allow a voltage level of the divided voltage to be the same as a voltage level of the reference voltage based on the compare result signal.