[plug] Mobile .mp3 results to date

[Brad Campbell]

"McMeikan, Andrew" wrote:
> 
> Hi,
>         I was thinking of the linear way, and been playing with a switching
> reg to keep the 12v up if the battery gets flat, any chance of a prelim
> circuit description or cost estimate?  Your death toll is impressive, I
> admire your determination if not your recklessness :)
> 

Well, there is less than $50 worth of parts in it at the moment.. roughly
It's a push-pull switching converter, running at 220khz.
Based on a TL494 Switching Controller.
Uses 2 IRF Hexfets for the switching.
Half bridge rectification with a centre-tap for all secondary windings.
Transformer is wound around a standard Phillips Feroxcube Transformer core
available off the shelf from Farnell comonents (The hardest bit to source)

Will run down to about 9v with a good low-impedance supply.
Gives +/- 5v  +/- 12v and 3.3v, plus power good signal and all other
relevant ATX signals..
Seems to be stable at the moment. The biggest problem is ripple on the +5 and
+12
rails.. We have about 1v p-p ripple at the moment on both rails, but the more
we work at it, the lower it gets.
We are working on sourcing ATX connectors at the moment.. They are easy to get
hold of, but only if your gonna buy 10,000 or so :p)

Brad....