Buck+half bridge (d=50%) topology applied to very low voltage power converters

Abstract

Buck+Half Bridge (d=50%) topology is a very suitable circuit for low output voltage, high output current applications with a wide input voltage range. Its small signal transfer function is very complex and should be considered to optimize the dynamic response, efficiency and size of the power converter. Small signal and large signal behavior of this topology are analyzed through their corresponding average models. Design guidelines, drawn from this analysis, are applied on two low-voltage (1.5 V) wide input voltage prototypes to validate the goodness of this topology.