self-energized synchronous rectifer circuit?

Hi all -

I've been reading a little about synchronous rectifiers as used in a 
switching power supply.  I've also seen some references to a 
"self-energized" version of the synchronous rectifier which could be used
in 
small signal rectification applications.

Has anyone seen a complete schematic for a self-energized syunchrnous 
rectifier circuit?

I've tried Google but most are references to "FreePatent", "IEEE", and 
"PatentStorm"...

Thanks

Dave