Patent ID: 8125203

Claim:
A PFC controller which controls switching elements of a plurality of voltage step-up chopper circuits arranged in parallel between an input terminal and an output terminal, comprising: a first circuit which generates one of switch control signals for one of said switching elements in one of said voltage step-up chopper circuits; and a second circuit which generates other switch control signals whose phases are shifted from a phase of said one of the switch control signals for said other switching elements in said other voltage step-up chopper circuits, wherein said second circuit includes: a first counter which counts clock signals by a cycle unit of said one of the switch control signals; a second counter which counts clock signals by a cycle unit having a phase shifted from that of said one of the switch control signals by a predetermined phase difference; and a first register which holds a value counted by said first counter corresponding to a period of a first-level state of said one of the switch control signals, and wherein said other switch control signal turns on the other switching element when said second counter starts counting and turns off said other switching element with a timing in which the value counted by said second counter matches the value held in said first register.