| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching-type power supply that reduces the circuit scale of a synchronous control circuit and uniformly generates a plurality of synchronous drive signals. SOLUTION: A single synchronous control circuit 4 is provided for a plurality of synchronous rectification metal-oxide-semiconductor field-effect transistors (MOSFETs) Qs1 and Qs2. The synchronous control circuit 4 generates a synchronous drive source signal Vg-s for controlling the MOSFETs Qs1 and Qs2, based on gate signals Vga and Vgb respectively controlling the ON/OFF of two main switching elements and respective inter-terminal voltage signals Vds1 and Vds2 of the MOSFETs Qs1 and Qs2. AND circuits 45 and 46 output synchronous drive signals Vgs1 and Vgs2 to the gates of the MOSFETs Qs1 and Qs2 as a logical product signal of the gate signals Vga and Vgb, respectively, corresponding to the main switching elements and the synchronous drive source signal Vg-s. The synchronous rectification MOSFETs Qs1 and Qs2 are turned on and off alternately, in synchronization with the ON timing of the main switching elements. COPYRIGHT: (C)2010,JPO&INPIT |
