A power supply circuit (300) for a display device such as a liquid crystal outputs a boosted supply voltage VDD2 during normal operation, and generates a non-boosted supply voltage VDD2 having a voltage lower than that during the normal display operation by controlling the switches for switching the output within the power supply circuit (300) during a power save mode. The non-boosted supply voltage is supplied to the analog circuits of a driving circuit (100) so that the power consumption at the analog circuits is reduced. By controlling the switch for switching the output within the power supply circuit and the supply of the power supply clock, the circuit can be switched, in the power save mode, to either a mode where a lower supply voltage is generated or to a mode where the power supply is turned off.