PURPOSE: To provide a low-coast power supply equipment of simple circuit constitution, which can output a high-frequency voltage with little low-frequency ripple without lowering the power factor of input from commercial power supply.
CONSTITUTION: A first chopper circuit 6A operates for the whole period, while a second chopper circuit 8B operates for the period during which the output voltage of a rectifier circuit 3 is not higher than a predetermined voltage. In the valley part of a rectifier output voltage, both of the two chopper circuits 6A, 6B operate and a capacitor C0 is sufficiently charged with electricity also in the valley part so that the low-frequency ripple of the output voltage of a chopper-type smoothing circuit 6 does not increase even if the capacity of the capacitor C0 is set low. Thus, it is possible to output an almost constant low-ripple high-frequency voltage without deteriorating the power factor of input from a commercial power supply 1, to reduce the capacity of the smoothing capacitor C0 and to miniaturize the capacitor C0.
KAMIOKA ATSUSHI
MITANI MASATAKA
ERIGUCHI HIROYASU
