It's pretty typical to use a gate-drive transformer in forward-mode
when you need a loosely regulated low power isolated supply.

You can easily drive the primary of a gate drive transformer with an
H-bridge type circuit .. you can use 74xx buffers, emitter followers,
etc.
Rectify the secondary and you have a low current isolated loosely
regulated supply. It's a forward mode converter so Vout is
proportional to Vin.

A look at Coilcraft shows gate drive transformers for $1 in low quantity.


--
Martin K.
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist