A display device includes a display panel including pixels, a data driver providing data signals to the pixels, a scan driver providing scan signals to the pixels, a DC-DC converter converting an input voltage to a power supply voltage and supplying the power supply voltage to the display panel, a feedback circuit having a variable impedance and providing a feedback path of the power supply voltage to the DC-DC converter by receiving the power supply voltage supplied from the DC-DC converter to the display panel and providing an error signal corresponding to a difference between the feedback voltage and a reference voltage to the DC-DC converter, and a controller controlling the data driver and the scan driver, calculating a panel load of the display panel based on input image data, and adjusting the variable impedance of the feedback circuit according to the calculated panel load.