Sure. My app was in a 12 volt environment.

The PIC/DAC are providing the REFERENCE voltage for the regulator. You
normally use a voltage divider from the regulator o/p to the error amp
input. For example, using a PIC/DAC to get a range of reference voltage
from 0 to 4 volts, if you use a 6 to 1 voltage divider, the output voltage
can vary from 0 to 24 volts.

I'm just suggesting an approach - as I said, I haven't followed the thread
in detail so I'm don't recall the exact requirements.

The resolution of the DAC (8 bit, 10 bit, 12 bit, etc) determine the step
size of your output voltage.

You can have a supply that goes from -25 to + 25, or any other range - by
adjusting the voltage divider, and possibly offsetting the DAC output (from
-2 to +2 volts, using another op amp).

Larry

At 02:11 PM 11/3/2002 -0500, you wrote:
>I'm don't understand your idea 100%, yet, but from what I see, wouldn't that
>limit me to a regulation between 0 and +Vcc (ie: 5V)?? The 317/337 combo I am
>using lets me have 0-25 and -25 - 0 (since I am using a stepdown transformer
>to 50V). I couldn't accomplish this with a DAC, could I?

Larry Bradley
Orleans (Ottawa), Ontario, CANADA

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