SEMICONDUCTOR INTEGRATED CIRCUIT

摘要

PROBLEM TO BE SOLVED: To solve a problem that the number of components increases since a coupling capacitor for converting a DC level between circuits is provided outside a semiconductor integrated circuit. SOLUTION: A high-pass filter 34 of a cutoff frequency fCis constituted of a coupling capacitor C1for performing a DC cut between circuits 22, 24, and an equivalent resistance RSCdue to a switched capacitor circuit 28. A capacitor CSCto be charged/discharged of the switched capacitor circuit 28 or a switching frequency fSCis set small, RSCbecomes great and C1with respect to the predetermined fCcan be reduced in response to RSC. Thus, the high-pass filter 34 including C1can be integrated on a chip of an IC 20. COPYRIGHT: (C)2007,JPO&INPIT