On 8/1/06, Gerhard Fiedler wrote: > Vasile Surducan wrote: > > > On 7/31/06, Mauricio Jancic wrote: > >> I wanted to keep the circuit as simple as it is now, but that's not a > >> mandate. What I certanly don't want to do is to make a circuit that has > >> very low efficiency, since it will have to run on batteries > > > -instead of PWM regulated voltage supply change the config for current > > supply (you need a pnp and a few resistors), then you'll not be forced > > to use a small range of the PWM resolution and the variation of the > > supply (which I understand it's a battery) in quite large limits will > > not influence the measurement accuracy as it probably does now. > > > > You probably know there are OP AMP with very small sourcing current, > > single power supply and rail to rail output, made just for battery > > applications... > > Isn't both of this (a linear regulator providing a lower voltage for the > PWM, op amp driving the output) low on the efficiency scale? I still think > that a switcher that provides a low voltage plus maybe PWM sounds like the > better deal. What's the problem with this? Noise and price I think. There are only a few small noise switchers on the market, most of them made by Linear Technology. But probably there are others. My opinion is that you want an accurate sensor, then avoid noise. greetings, Vasile > > Gerhard > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist