Patent ID: 6449176
Filing Date: 2002-09-10
Classification: H02M

Abstract:
A switching power supply comprising:a saturable inductor serially coupled to a secondary side winding of a transformer; a smoothing circuit for smoothing an AC output of the secondary side winding of the transformer; an operational amplifier for comparing a DC output voltage from the smoothing circuit and a reference voltage; and a control voltage generating circuit for generating a control voltage of the saturable inductor based on a result of the comparison by the operational amplifier, wherein the control voltage generating circuit includes: a transistor, parallel coupled to output lines of the secondary side winding of the transformer, a base of the transistor being coupled to receive an output voltage from the operational amplifier; a diode connected between a collector of the transistor and an output terminal of the saturable inductor; and a resistor coupled between a collector of the transistor and the base of the transistor.