PWM power supply with synchronous rectifier and synchronizing oscillator

摘要

There is disclosed a power supply device having a transformer including primary and secondary windings, for generating in said secondary winding a high voltage output corresponding to power supplied to said primary winding, a first switch for on-off switching power supplied to the primary winding of said transformer, a first signal generator for supplying a switching signal at a first frequency to said first switch, a rectifier for rectifying the high voltage output generated in the secondary winding of said transformer, and controller including a second signal generator for supplying a modulating signal at a second frequency lower than said first frequency, for modulating the output of said rectifier by means of controlling the power supplied to the primary winding of said transformer in accordance with said modulating signal.