SEMICONDUCTOR CIRCUIT

PROBLEM TO BE SOLVED: To prevent malfunction of a semiconductor circuit.SOLUTION: A semiconductor circuit includes; a first power-supply terminal receiving a first voltage VDD1; a second power-supply terminal receiving a second voltage VDD2 different from the first voltage VDD1; a regulator circuit 2 regulating the second voltage VDD2 and outputting the regulated second voltage VDD2 as an output voltage to an output terminal; an ESD protection circuit 6 for discharging ESD occurring at the output terminal; and a level shift circuit 1 shifting the magnitude of the first voltage VDD1 to the magnitude of the second voltage VDD2 and outputting a control signal to electrically isolate the regulator circuit 2 and the ESD protection circuit 6 according to the presence or absence of the application of the first and second voltages VDD1 and VDD2.