Before you go willy-nilly sticking a digital pot in, though, you need
to be certain that the voltages on the pot are not past it's specs.

For example, with Microchip's digital pots (IIRC), you had BETTER
not put more than the supply voltage on any of the pins (at least,
according to the datasheet).

I don't know exactly what circuit you'll use, but just keep that in
mind.

Mike H.

>John Waters wrote:
>
>>I want to use my car battery to provide a range of variable d.c. from
>>0-12V,
>>but a standard regulator circuit doesn't fulfill the requirement, as I
>>want
>>the output voltage to be adjustable by software through a microcontroller,
>>could someone suggest how to do that?
>
>The key is: digital POT. Question is whether you can afford a wasteful
>linear regulator, or you need a switcher. The LM317 I believe is the
>standard for this sort of thing. Of course, you might need an LDO (low
>dropout) regulator...see TI, OnSemi, etc. for an adjustable LDO linear
>regulator. All of these use some sort of resistive divider to fix
>voltage, and with a digital POT in there (Microchip makes some nice
>ones, the MCP4xxxx series), you're all set.
>
>If you are looking for switchers, National makes a number of adjustable
>ones. I've used the LM2576-ADJ, but that's a high current (3A) part.
>They make low-current ones too. Check them out. "dropout", i.e. min
>input-output differential is about 3V.
>
>Cheers,
>-Ishaan
>
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