A display device includes a display unit including a plurality of pixels, a scan driver applying a scan signal to a plurality of scan lines, a data driver applying a data signal to a plurality of data lines, and a power supply unit supplying a driving voltage to at least one among the display unit, the scan driver, and the data driver. The power supply unit includes an inductor connected between an input terminal to which an input voltage is input and a driving voltage output terminal to which the driving voltage is output, a switch connected between the inductor and a ground, and a switch controller outputting a first ramp pulse having a first frequency at a first load of the display device and outputting a second ramp pulse having a second frequency at a second load of the display device.