| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply apparatus which controls irregular rises of a DC voltage under a light load condition, also controls a rush current and may be formed with fewer number of elements than that of the existing apparatus. SOLUTION: An AC power supply AC is rectified by a rectifying circuit DB. A capacitor C0 is selectively connected for rectifying an output of the rectifying circuit DB and power supply of an inverter circuit 2 via a switching element SW0 . The inverter circuit 2 uses a switching element Q2 in common, as an input distortion improving circuit 1, which is also operating as a voltage rise chopper circuit. After the predetermined time has passed from turning on of the power supply, the switching element SW0 is controlled, to connect a capacitor C0 to a resistor R1 and the capacitor C0 is connected to the switching elements Q1 , Q2 when a load is normal. Thereby, a rush current generated immediately after turning on of the power supply can be prevented, and there is no rise of voltage across the capacitor C0 during a light load. Since the capacitor C0 is used in common for a couple of functions with the switching element SW0 , number of parts may be reduced. |
