Its an idea...=20
use a different pic to drive a pwm from the adc result... this can be
coupled through an opto to a capture module... no common anything
required...

Steve

-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of
Anthony Toft
Sent: 07 July 2015 17:15
To: piclist@mit.edu
Subject: [PIC] Using the ADC without a common ground

Hi folks,

I am looking at using a PIC24FV32KA302 for a project that will include a
cheap solar/battery charger controller device. I will be powering the
controller board (my project) from the load output (assuming the battery
keeps it running when the sun goes down) and it will be using a 3.3v voltag=
e
regulator (one of the Murata switchers) and I'd like to use a couple of the
ADC channels to measure the panel and battery voltages.

I have used the ADC to measure voltages in the past, using a voltage divide=
r
to scale the voltage between Vss and Vdd but that has always been when the
measured voltage is referenced to the same ground as the uC. In this case I
don't know if the grounds will be common, and I am wondering how I can
measure these voltages.

So far I have come up with using an instrumentation amplifier, but I am
interested in alternative solutions.

Thanks for any ideas!
--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/chang=
e
your membership options at http://mailman.mit.edu/mailman/listinfo/piclist

--=20
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.