Patent ID: 7826297

Claim:
A power supply switching circuit that switches over a plurality of power supply voltages used within a nonvolatile memory to output the plurality of switched power supply voltages to a power supply voltage output terminal, comprising: a first power supply voltage input terminal to which a first power supply voltage being a highest voltage among the plurality of power supply voltages is input; a second power supply voltage input terminal to which a second power supply voltage being a voltage lower than the first power supply voltage is input; an enhancement type PMOS transistor that is disposed between the first power supply voltage input terminal and the power supply voltage output terminal, and has a back gate connected to the first power supply voltage; a depletion type NMOS transistor that is disposed between the second power supply voltage input terminal and the power supply voltage output terminal, and has a back gate connected to a ground voltage VSS; a first level shift circuit that converts an amplitude of a first control signal for controlling a gate of the enhancement type PMOS transistor from the first power supply voltage into the ground voltage VSS; and a second level shift circuit that converts an amplitude of a second control signal for controlling a gate of the depletion type NMOS transistor from the first power supply voltage into the ground voltage VSS.