Patent ID: 8126515

Claim:
A semiconductor integrated circuit comprising: a pair of antenna terminals connectable with an antenna; a rectifier operable to rectify a radio frequency signal supplied through the pair of antenna terminals thereby to output a direct-current voltage to an inside source line; a source-voltage terminal for supply of a source voltage from outside; a shunt regulator including a pull-down transistor connected between the inside source line and a ground, and passing a pull-down current through the pull-down transistor in response to a rise of a voltage of the inside source line to or above a first set voltage; and a series regulator including a pull-up transistor connected between the source-voltage terminal and inside source line, and passing a pull-up current through the pull-up transistor in response to a fall of the voltage of the inside source line to or below a second set voltage, wherein the first set voltage is set to be higher than the second set voltage in voltage level.