PURPOSE: To reduce the volume of an LSI chip, by constituting the circuit that no holding capacitor is required in a switched capacitor circuit.

CONSTITUTION: One end of a switched capacticor circuit 10 is connected to an input terminal 1 of a filter 1 and another end is connected to switches 7-1 and 7-2 which alternately switch a switched capacitor circuit 20 and ground with a prescribed period. The circuit 20 consists of a switched capacitor 4 which makes charging with a switch 7-2 turned on and a switch 7-3 turned on and makes discharge with a switch 7-4 turned on and a switch 7-3 turned off when the switch 7-1 turns on and the switch 7-2 turns off, a capacitor 5 and an operational amplifier 8. Further, the circuit is constituted so that a product V2(C3+C2) between an output terminal voltage V2 and the sum of capacitors 4 and 5 can be a function of a product between a capacitance value C1 of a capacitor 3 and a potential difference of an input voltage V1 for one period.