On Fri, 15 Apr 2011 19:46 -0400, "V G"  wrote:

> But I don't understand why the high side sensing is difficult. Isn't it
> the
> same idea? Just measure the voltage drop across the resistor? I'll just
> sample some nice diff amp from LT or something.

Operating dual supply it would be no problem but single supply you will
need a good single supply diff amp or buffer a divider to feed a regular
diff amp reference. So choosing your diff amp will be an exercise in
datasheet comprehension.

> With the low side sensing, I can just use a good opamp?

Even an LM324 would work on the low side. It just needs to have inputs
and outputs valid to ground.

Cheers,

Bob

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