Semiconductor integrated circuit device and ic card using the same

Abstract

The present invention enables a power-supply voltage terminal and an internal circuit to be isolated from each other in a noncontact operation without largely increasing a chip area in a semiconductor integrated circuit device for an IC card. A semiconductor integrated circuit device comprises: a first power supply circuit for rectifying and smoothing an AC signal supplied from an antenna to an antenna terminal, thereby obtaining a DC voltage in a first power-supply line; a second power supply circuit comprising a voltage control circuit for controlling gate terminal voltage of a first MOS transistor disposed between a power supply terminal to which power is input from the outside and the first power supply line; a substrate potential control circuit for forming source voltage of the first MOS transistor as a substrate voltage; and a second MOS transistor which makes substrate voltage and gate voltage of the first MOS transistor conductive in the case of using the voltage generated by the first power supply circuit as a power supply, and which makes the substrate voltage and the gate voltage nonconductive in the case of using a power supply from an external terminal.