Hi Peter

The app. note on the Max630 describes such a supply, although it does use
two chips for the different functions. I've attached it to you only so as
not to clog the group. (550Kb)

I would use a switching reg for step up only, and a simple linear reg on
the 12V side where you have lots of power and don't need the same efficiency.

Regards
Roland


At 02:29 PM 16/02/04 +1100, you wrote:
>Hi All,
>Might be stumbling down the wrong track, but worth investigating
>anyway...
>
>Can anyone recommend a switch mode regulator that will do boost
>and buck regulation?
>
>Basic usage is for a system that runs in a car, but requires
>backup battery. It also requires good 3.6V regulation.
>Current consumption at 3.6V is around 200ma max. backup battery
>is presently 3xAAA NiMh 650mA
>
>My idea is the battery can also be feed into the input of
>the switch mode so to maintain good regulation..
>
>Any help much appreciated as always :)
>
>Regards,
>Peter Mcalpine
>Sydney, Australia
>
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Regards
Roland Jollivet


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