| 摘要 |
PROBLEM TO BE SOLVED: To provide a DC-DC converter in which the reverse current is low when the load is reduced and a high conversion efficiency can be maintained during light load, and to provide its control circuit. SOLUTION: When a control circuit 11a is driven by PWM system, the control circuit 11a operates in synchronous rectification system for turning a first MOS transistor T1 and a second MOS transistor T2 on/off complementarily based on an L level operation switching signal CS. When the control circuit 11a is driven by PFM system, the control circuit 11a operates in diode rectification system for operating the second MOS transistor as an ideal diode by a second comparator 30 based on an H level operation switching signal CS. COPYRIGHT: (C)2008,JPO&INPIT |
