Circuit offers improved active rectification:
02/06/03 EDN-Design Ideas / Rectifiers convert ac
signals to dc. You can combine a diode and a load
resistor to create a half-wave rectifier, provided
that the amplitude of the ac source is much larger
than the forward drop of the diode (typically 0.6V).
Unfortunately, you can't use this method to rectify
signals that are smaller than a diode drop...
Method provides self timing for synchronous
rectifiers: 05/16/2002 EDN - Design Ideas /
Synchronous rectifiers are MOSFETs, driven in such a
way as to perform a rectifying function. They often
take the place of diodes in the output-rectification
stage of switching power converters, because of
their lower on-state power loss. In power circuits,
synchronous rectifiers are often complicated to use
because of timing issues..