| 摘要 |
PROBLEM TO BE SOLVED: To obtain an efficient DC power supply without causing power loss even in the case of a light load. SOLUTION: An average value signal formation circuit 25 of a DC-DC converter 11 averages a control signal being outputted from a second control circuit 13, outputs it to a first control circuit 25 of a power factor improvement circuit 24 as an average value signal. A first control circuit 26 of the power factor improvement circuit 24 uses the DC voltage of a capacitor 22 and a diode 21 as a DC voltage, turns on/off a first switching means 8 after a specific amount of time, and stops the control of the first switching means 8 when the level of the average value signal reaches a preset reference value or less. |
