| 摘要 |
PROBLEM TO BE SOLVED: To reduce the loss at the time of rectification and current returning operation by turning a MOS transistor for rectification on and turning an inversion-side MOS transistors off at the time of rectification, and turning both MOS transistors on at the time other than this. SOLUTION: MOS transistors M1 -M4 are enhancement MOS transistors which are turned on by high levels and off by low levels, and constitute a full-bridge inverter. And M1 and M4 , and M2 and M3 form pairs, and the primary winding of a transformer T1 is driven through a capacitor C1 inserted for preventing the polarized magnetism of the transformer T1 . Besides, MOS transistors M5 , M6 being devices for synchronous rectification become on the inversion side, and are so controlled that they may be on in periods other than controlled-to-off periods. And rectifying operation is performed in the on-periods, and a current is supplied to a load RL through a smoothing circuit consisting of an inductance L1 and a capacitor C1 , and a return current is caused to flow after the rectifying operation. As the result, it becomes possible to reduce the loss of a power device. |
