| 摘要 |
PROBLEM TO BE SOLVED: To provide a DC converter for reducing a loss during a small load, and improving the efficiency. SOLUTION: The DC converter has: a synchronous rectifying circuit having switching circuits Qm, Qs for turning on/off a DC voltage from a DC power supply Vdc1 and supplying it to a primary winding 5a, a switch Qr turned on/off in synchronization with turnon and turnoff of the switching circuits and a switch Qf turned on/off complementary to the switch Qr, and rectifying a voltage from a secondary winding 5b; a rectifying circuit having a diode D3 connected to the switch Qr in parallel and a diode D4 connected to the switch Qf in parallel; smoothing circuits L1, C3 for smoothing outputs rectified by the synchronous rectifying circuit and the rectifying circuit; and synchronous rectifying element controlling circuits Qd1-Qd4, SW2 provided between both ends of a tertiary winding 5c and control terminals of the switches Qr, Qf, interrupting a voltage across the tertiary winding 5c applied to the control terminals of the switches Qr, Qf during small load, and turning off the switches Qr, Qf. COPYRIGHT: (C)2007,JPO&INPIT
|
