A voltage control circuit is connected to a voltage source. The voltage control circuit changes voltages of n different values and outputs them to an output node of the voltage control circuit according to control signals. A first switch element is connected between the output node of the voltage control circuit and a reference voltage node, and a second switch element is connected between the output node of the voltage control circuit and an output node of the voltage source. The first switch element is controlled so as to be conductive when the voltage control circuit changes the voltage of the output node from a first voltage to a second voltage that is lower than the first voltage, and the second switch element is controlled so as to be conductive when the voltage control circuit changes the voltage of the output node from a second voltage to a first voltage.