[sdiy] switched mode PSU design

[Steve Lenham]

>
> I'm hunting for a switched mode PSU design which is small enough to fit in 
> a
> wall wart. Anyone got any suggestions?
>

David,

Try the "Topswitch" family of ICs (available from Farnell - just search for 
"topswitch" on their website). They contain pretty much an entire off-line 
switching PSU on one chip, in DIL8/TO220 etc. depending on power rating.

The difficulty with any off-line design is likely to be in sourcing the 
correct high-frequency transformer - they don't tend to be available 
"off-the-shelf". If you find a good source in small quantities then I'd be 
interested to hear about it.

Obviously there are increasing numbers of ready-made switchmode wallwarts 
commercially available, but I'm assuming you want something a bit 
non-standard - dual rails, perhaps?

Hope this helps,

Steve L.