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? Gerhard -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist