Patent ID: 6246592
Filing Date: 2001-06-12
Classification: H02M,Y02B

Abstract:
A power supply comprising:a transformer-coupled power converter operative to convert an input direct current (DC) voltage to an intermediate DC voltage, said transformer-coupled power converter including:a transformer having at least one primary-side winding and at least one secondary-side winding;at least one pair of free-running primary-side power switches operative to generate a nearly 100% duty cycle secondary-side voltage; andat least one pair of secondary-side rectifiers operative to rectify a secondary-side current from said at least one secondary-side winding to produce said intermediate DC voltage;a buck power converter operative to produce a regulated output voltage from said intermediate DC voltage, said buck output converter including a forward buck switch in series with said at least one secondary-side winding of said transformer, and a freewheeling switch in parallel with said forward buck switch and said at least one secondary-side winding, said forward buck switch being controlled by a control signal; anda pulse width modulation (PWM) control circuit operative to monitor said regulated output voltage and to generate said control signal for said forward buck switch so as to maintain said regulated output voltage within a predetermined regulated range.