| 摘要 |
PROBLEM TO BE SOLVED: To stably secure a control voltage with the reduction of power consumption in a standby mode of a switching power supply including a power factor improvement circuit.SOLUTION: A switching power supply 1 includes: a control winding L2 which magnetically couples with an inductor L1 provided in a power factor improvement circuit 20; and a control unit 40 which is operated by a control voltage produced on the control winding L2, to perform switching control of a switch element Q1 provided in the power factor improvement circuit 20. In a standby mode, the control unit 40 sets a longer switching period of the switch element Q1, provided in the power factor improvement circuit 20, as compared to a stationary operating state other than the standby mode.SELECTED DRAWING: Figure 1 |
