Hi,
	If you replied with that answer I'm sorry but I missed it. The
onlyone I have from you is the one asking power requirements.

	I think it's a good idea, I just don't want to kill the other
options and hear everyone that has an idea, then decide the best one.

	I think the efficiency of the system that you are proposing can be
very good, and also the accuracy.

	Thanks

Mauricio Jancic
Janso Desarrollos
www.janso.com.ar
info@janso.com.ar
(54) 11-4542-3519
 

> -----Original Message-----
> From: piclist-bounces@mit.edu 
> [mailto:piclist-bounces@mit.edu] On Behalf Of Gerhard Fiedler
> Sent: Tuesday, August 01, 2006 9:17 AM
> To: piclist@mit.edu
> Subject: Re: [EE] Low voltage variable power supply
> 
> Vasile Surducan wrote:
> 
> > On 7/31/06, Mauricio Jancic <info@janso.com.ar> 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
> 
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