PFC SIGNAL GENERATION CIRCUIT, PFC CONTROL SYSTEM USING SAME, AND PFC CONTROL METHOD

摘要

A PFC signal generation circuit for generating a PFC signal for controlling a PFC circuit having a first inductor (L1) connected to a first switch (NM1), and a second inductor (L2) connected to a second switch (NM2). The invention is equipped with: a first control signal output circuit (109) for outputting a first PFC signal for turning a first switch (NM1) on, at the timing when zero current is detected in the first inductor (L1); and a timing adjustment circuit (113) for generating a control signal (set2) for turning the second switch (NM2) on after waiting until the target timing, when the timing when zero current is detected in the second inductor (L2) is earlier than the target timing, and turning the second switch (NM2) on at the target timing in the next cycle when the same is later than the allowable period following the target timing; and a second control signal output circuit (117) for generating a second PFC signal for turning the second switch on according to the control signal (set2).