| 摘要 |
An efficient power factor correcting (PFC) circuit is constituted such that one terminal of an input rectifier (12) from which a pulsating voltage is obtained, is connected to a connection mid point of one terminal of a primary winding (15a) and the other terminal of an auxiliary winding (15c) wound in phase on a converter transformer (15), by means of a series circuit of a choke coil (13) and a first diode (14); one terminal of the auxiliary winding (15c) of the converter transformer (15) is connected to the other terminal of the input rectifier (12) through a first capacitor (16) and at the same time the other terminal of the primary winding (15a) is connected to the other terminal of the input rectifier (12) through a switching device (17); a secondary winding (15b) wound in counter phase with the primary winding (15a) for the converter transformer (15) is connected to a DC voltage output terminal (19a,19b) through a rectifying circuit (18); the DC voltage output terminal (19a) is connected to an input side of a pulse width modulation control circuit (20); and an output terminal of the pulse width modulation circuit (20) is connected to a control electrode of the switching device (17). <IMAGE> |
