A power supply includes a boost circuit having a first boost circuit configured to output a first driving voltage to be supplied to the display panel by stepping unit an input voltage and a second boost circuit configured to output a second driving voltage to be supplied to the display panel by stepping down the input voltage, and a correction circuit configured to output a correction signal based on a result obtained by sensing the input voltage, and controls output efficiency of the boost circuit based on the input voltage and current sensed from the display panel.