A display device includes: a display panel on which a plurality of pixels are disposed; a timing controller configured to receive Nth frame data and (N+1)th frame data and output a luminance control signal; and a power supply configured to output a reference voltage from a plurality of reference voltages each having a different level in response to the luminance control signal, in which output luminance of the plurality of pixels is determined according to the level of the reference voltage thereby maximizing an HDR effect.