Efficiency improvement techniques of high current low voltage rectifiers using MOSFETs

This paper presents techniques for loss minimization in ultra-high current low-voltage power supplies. The use of synchronous rectification using MOSFETs offers the advantage of reducing the conduction losses significantly compared to conventional rectification, with the possibility of achieving almost zero conduction losses through parallel connection. The design considerations for paralleling MOSFETs are briefly discussed, as paralleling is required for satisfying the high current requirements. Moreover, cryogenic operation of MOSFETs offers further reduction of the conduction losses. MOSFETs with various ratings are tested to evaluate the reduction in the on-resistance at liquid nitrogen temperature compared to the normal operating temperature. An estimate for the rectifier power losses including the cooling power is compared in order to show if it is advantageous for this specific application.