Toward the “ideal diode” using power MOSFET in full wave synchronous rectifiers for low voltage power supplies

Abstract

Synchronous rectifiers can improve power efficiency, particularly in low-voltage, medium power applications. By using power MOSFET with low Ron resistance in parallel with classical diode, the diode function is closely to ldquoideal dioderdquo. The paper presents the simulation results of a full wave rectifier circuits with control circuit made by the known IC (charge pumps, CMOS analogue switches and MOSFETpsilas). The known IC can be used to design a new IC for full wave synchronous rectifier. The main applications of synchronous rectifiers are for DC-DC converter but we propose the extension to the general purpose rectifier circuit. For low voltage output rectifiers (smaller than 5 V) the efficiency can increase with 15% by using synchronous technique. In the paper is presented a new IC structure for control the full wave synchronous rectifier.