Patent ID: 7596009
Filing Date: 2009-09-29
Classification: H02M,Y02B

Abstract:
1. A double-ended isolated DC-DC converter comprising: a main transformer including at least a primary coil and a secondary coil; first and second power switches connected to a primary side of the main transformer; a primary side control circuit arranged to control switching operations of the first and second power switches; first and second synchronous rectifiers connected to a secondary side of the main transformer; at least one choke coil; a first edge signal generating circuit arranged to generate, based a signal output from the primary side control circuit, a first turn-off edge signal and a first turn-on edge signal substantially corresponding to a timing of turn-on and turn-off of the first power switch, respectively; a second edge signal generating circuit arranged to generate, based on a signal output from the primary side control circuit, a second turn-off edge signal and a second turn-on edge signal substantially corresponding to a timing of turn-on and turn-off of the second power switch, respectively; a first pulse transformer arranged to transmit the first turn-off edge signal and the first turn-on edge signal to the secondary side; a second pulse transformer arranged to transmit the second turn-off edge signal and the second turn-on edge signal to the secondary side; a first synchronous rectifier control circuit arranged to turn off the first synchronous rectifier in response to the first turn-off edge signal transmitted from the first pulse transformer and turn on the first synchronous rectifier in response to the first turn-on edge signal transmitted from the first pulse transformer; and a second synchronous rectifier control circuit arranged to turn off the second synchronous rectifier in response to the second turn-off edge signal transmitted from the second pulse transformer and turn on the second synchronous rectifier in response to the second turn-on edge signal transmitted from the second pulse transformer; wherein the first power switch and the first synchronous rectifier are driven with substantially complementary timing; and the second power switch and the second synchronous rectifier are driven with substantially complementary timing.