Patent ID: 6567278
Filing Date: 2003-05-20
Classification: H02M

Abstract:
A power supply comprising a DC-DC converter which comprises(a) a first transformer having a primary winding and a secondary winding, said primary winding and said secondary winding of said first transformer having the same winding polarity; (b) a second transformer having a primary winding and a secondary winding, said primary winding and said secondary winding of said second transformer having opposite winding polarities; said secondary winding of said first transformer having a terminal which is a first transformer output terminal, another terminal of said secondary winding of said first transformer and a terminal of said secondary winding of said second transformer being connected with each other at a node which is a second transformer output terminal, and said secondary winding of said second transformer having a terminal which is a third transformer output terminal; (c) a first H-bridge switching circuit for selectively connecting a primary DC source to the primary winding of said first transformer, said first H-bridge switching circuit having a leading leg and a lagging leg, each of these legs including switching elements; (d) a second H-bridge switching circuit for selectively connecting said primary DC source to the primary winding of said second transformer, said second H-bridge switching circuit having a leading leg and a lagging leg, each of these legs including switching elements; (e) a bridge rectifier circuit connected to the secondary windings of said first and second transformers; (f) a control circuit for providing (f.1) a first set of control pulses for effecting switching of switching elements of said leading leg of said first H-bridge switching circuit, (f.2) a second set of control pulses for effecting switching of switching elements of said lagging leg of said first H-bridge switching circuit, said second set of control pulses having an adjustable first phase delay with respect to said first set of control pulses, (f.3) a third set of control pulses for effecting switching of switching elements of said leading leg of said second H-bridge switching circuit, said third set of control pulses having an adjustable second phase delay with respect to said first set of control pulses, (f.4) a fourth set of control pulses for effecting switching of switching elements of said lagging leg of said second H-bridge switching circuit, said fourth set of control pulses having an adjustable third phase delay with respect to said third set of control pulses.