Patent ID: 7738266
Filing Date: 2010-06-15
Classification: H02M,Y02B

Abstract:
1. A controller for a resonant discontinuous forward converter (RDFC), said forward converter including a transformer with first and second matched polarity windings and a switch to switch dc power to said first winding of said transformer, said converter further having a dc output coupled to said second winding of said transformer, and wherein said controller has two modes, a first operational mode during which said switch is controlled to switch said dc power at a frequency which substantially coincides with a resonant frequency of operation of said RDFC such that said RDFC supplies power from said dc output, and a second, reduced power operational mode during which a drive to said switch is controlled to increase a proportion of time during which said switch is off, wherein said controller is configured to: control said switch to switch at a timing which is substantially synchronised with a timing of cycles of said resonant frequency of operation; and wherein in said second mode of operation said switch is controlled such that one or more of said resonant frequency cycles are skipped.