This paper presents a new family of circuits for single phase diode bridge rectifiers capable of drawing approximately sinusoidal current at unity power factor with high efficiency and minimum voltage stress across the switches. They can work as either boost or flyback converters. The circuits consist of a single-phase diode bridge rectifier, followed by a boost stage containing two switches-the main switch for controlling the output DC voltage and the auxiliary for achieving zero voltage switching (ZVS). The switching frequency of the converters is maintained constant. The paper explains the principle of operation and describes the analysis of each mode of operation for both boost and flyback converters. It also gives design criteria, derived from the mathematical analysis carried out, for achieving ZVS under all loading conditions. The simulation results obtained using PSPICE demonstrate the validity of the proposed converters.