Patent ID: 6650551
Filing Date: 2003-11-18
Classification: H02M,Y02B

Abstract:
In a soft-switching DC/DC converter including a positive voltage input terminal and a negative voltage input terminal interconnected by a semiconductor switching device, a transformer, and an output rectifier circuit coupled to a secondary winding of the transformer, an apparatus for clamping the voltage across the output rectifier circuit comprising:first and second clamp diodes connected in series across the positive and negative voltage input terminals; a resonant inductor coupled in series with a primary winding of the transformer; and a voltage clamp circuit, the voltage clamp circuit including an inductor mutually coupled with the resonant inductor, the inductor having a first terminal connected to one of an end or an intermediate tap of the resonant inductor and having a second terminal connected to a common node of the first and second clamp diodes, the voltage clamp circuit limiting the voltage at the output rectifier circuit.