Patent ID: 6370051
Filing Date: 2002-04-09
Classification: H02M

Abstract:
A forward converter circuit, comprising:a transformer having a primary winding and a secondary winding; a first switch coupled to said transformer and adapted to selectively couple a bus voltage terminal to a first terminal of said primary winding of said transformer, said first switch including an internal capacitor; a second switch coupled to said transformer and adapted to selectively couple a second terminal of said primary winding of said transformer to ground, said first switch including an internal capacitor, said first and second switches triggering in response to a first periodic gate control signal; a diode coupled between said bus voltage terminal and said second terminal of said primary winding of said transformer; a third switch coupled to said transformer and adapted to selectively couple said first terminal of said primary winding of said transformer to ground, said third switch including an internal capacitor, said third switch triggering in response to a second periodic gate control signal to increase a removal rate of magnetization current from said transformer, said second periodic gate control signal being substantially inverted with respect to said first periodic gate control signal; and a capacitor coupled in parallel with said second switch in addition to said internal capacitor of said second switch; wherein, power from said bus voltage terminal is transferred from said primary winding to said secondary winding of said transformer during a portion of an operational cycle of said forward converter circuit with said first and second switches in a conductive state, and at least said second and third switches change between non-conductive and conductive states at substantially zero voltage and zero current conditions.