Soft Transition Apparatus and Method for Switching Power Converters

摘要

An embodiment apparatus comprises a secondary synchronous rectifier and a secondary gate drive controller. The secondary gate drive controller coupled to a transformer winding comprises a secondary synchronous rectifier soft start signal generator configured to generate a plurality of soft start pulses, a pulse width modulation generator configured to generate a forward switch drive signal and a freewheeling switch drive signal based upon a signal across the transformer winding and a soft transition generator configured to generate a soft start freewheeling switch drive signal by gradually releasing the freewheeling switch drive signal during a soft start process.