Hi All, Ok, redesigning things again...
Considering using a digital pot as the calibration setting for my ambient light sensor, so just using it as the feedback resistor in my bufer stage. Any gotcha's I should know about, or other idiosyncracies?
Thanks, Charlie
Digital pot is RC-RC-RC-RC-RC... It will oscillate like hell if you don't dump it properly.
VLV
Vladimir Vassilevsky a écrit :
^^^^^ That sure is the word :-)
Also mind the tempco, which is good as a divider, but might not be so good as a resistor.
Fred Bartoli a écrit :
The carets should obviously underline "dump".
Not if the feedback comes from a tap... then it behaves like a compensated scope probe. BTDT. ...Jim Thompson
What do you expect from a digital guy? :)
Are you sure you need to make the adjustment there instead of twiddling bits? I.e., how much "extra" range do you have in your measurement circuitry that you could exploit?
When dealing with things like this, I tend to use integrating/ counting converters. So, I can just change the period to get the precision I need and massage the "readings" internally. "Calibration" is then just storing factors "someplace" (sometimes, this is a *volatile* parameter and the device can "relearn" its calibration data as part of normal operation)
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