On 4 Jun 2002 at 11:41, A.J. Tufgar wrote:

> Hello All,
>           I have a project that I'm working on that runs of two D cells
> in series.  I'm using a 16C711 that works from 2.5-5.5V.  On the ADC
> port I have a 3VDC pressure transducer with a output of 0-60mV.  When a
> certian pressure is reached a solenoid valve opens.
>
> Here's my problem.  I want this to be effecient on battery power so I'd
> like to run both sensor and pic at 2.5V trouble is even LDO's will
> dropout at about 2.7V.  The solenoid works to about 2.4V.
>
> What I was thinking of doing is not using a regulator so the voltage
> would vary over battery life about 1.6-1.25.  Vref (I have it set at
> about 70mV) should drop with respect to battery and so should the output
> of the sensor (it's a wheatstone bridge configuration).  I also have the
> pic calibrate on boot.  So these three attributes combined I would
> believe would be enough to not have to use a regulator.
>
> Any thoughts?  Any ideas on a reg that would output 2.5V until the
> voltage dropped below 2.5V?

Shunt Regulator. (Zener).
>
> Aaron
>
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>


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  |  __O    Thomas C. Sefranek  tcs@cmcorp.com
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