| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a synchronous rectification type switching power supply capable of suppressing degradation of efficiency due to increasing power loss. Ž<P>SOLUTION: The synchronous rectification type switching power supply 1 includes a switching circuit 80 for changing gate voltage of switching elements 141 and 142. The switching circuit 80 includes capacitors 81 and 82 which charge/discharge according to respective voltages of the third secondary winding 101d and the fourth secondary winding 101e, a switching element 184 whose gate is connected to the capacitor 81, and a switching element 183 whose gate is connected to the capacitor 82. The capacitor 81 discharges to the gate of the switching element 184 as the voltage of the third secondary winding 101d drops. If the electric charges discharged from the capacitor 81 come to be a predetermined quantity when the voltage of the third secondary winding 101d drops down to VG1, the switching element 184 comes to be on-state for discharging electric charges of the gate of the switching element 141. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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