Integrated-magnetic pre-converter networks for switchmode power converter circuits

The evolution details and design issues of novel pre converter approaches are presented, whereby the input voltage range capability of buck or buck-boost-derived DC-to-DC converters can be greatly extended. The integrated-magnetic forms of the concept use three passive circuit components and two diodes, and do not require any active switch elements. The preconverters also naturally translate the normally pulsating currents drawn by user power converters into nonpulsating forms whose AC ripple current magnitudes can be reduced to near-zero values by proper magnetics design. Small-signal modelling methods for examining the effects of the presence of preconverters on user converter circuits are presented