In this invention we introduce the concept of a fundamental switching cell with complimentary switchers s and a controlled dead time which is one of the embodiments of this invention. This fundamental switching cell can be used in isolated DC-DC Converter applications and also used for totem pole bridgeless power factor correction applications. One of the main embodiments of this invention describes a circuit wherein such a fundamental switching cell is used to transfer the power across a transformer towards secondary while providing power factor correction for the input line current while extracting the energy from the line and steering the low frequency ripple of the input current towards the bulk capacitor and regulating the voltage in the secondary of the transformer.