Synchronous Rectifier using P-MOSFET

278

04:08:02

A synchronous or active rectifier is a circuit that uses a MOSFET for rectification instead of a diode. The advantage of using a MOSFET is that the power lost in high current rectification is lower than with a diode. The other advantage is that the circuit using it need not be in continuous conduction mode.

Reverse Leakage current characteristics:
http://everycircuit.com/circuit/6468904220884992

It's forward quiescent current characteristics is identical.

The zener diode in the circuit prevents the driver's output voltage from swinging beyond 15V from the source of the MOSFET.

This circuit is based on @walkemm's ideal diode circuit:
http://everycircuit.com/circuit/6669969281777664

published 6 years ago

kiani

6 years ago

Doesn't The pmos has a body diode which in this config will be forward biased !?!,, also the load is on the low side, (i guess that doesn't matter so much..

PrathikP

6 years ago

The diode conducts briefly, very briefly before the PMOS turns on and the channel itself takes over conduction. Just link in all other synchronous converters. The advantage of a self driven synchronous rectifier is that it can be used in place of a diode in discontinuous mode converters, unlike the type where the rectifier MOSFET get the compliment of the PWM of the chopper MOSFET, because of which the inductor must be in CCM. Crap, I completely forgot to put this in the discription

kiani

6 years ago

Thank you for explaining, i have't worked with mosfets as diodes.. My work with SMPS, only limits to diodes,, but i get the overview.

PrathikP

6 years ago

My pleasure

add comment in editor

EveryCircuit is an easy to use, highly interactive circuit simulator and schematic capture tool. Real-time circuit simulation, interactivity, and dynamic visualization make it a must have application for professionals and academia. EveryCircuit user community has collaboratively created the largest searchable library of circuit designs. EveryCircuit app runs online in popular browsers and on mobile phones and tablets, enabling you to capture design ideas and learn electronics on the go.