Question for the electronics guys

[Amphiprion]

OK, so I have a dual power supply on which I want to monitor the current draw. I'm using a high side current sense amplifier (MAX4080) with a 10mohm series resistor on the +15V rail into one of the ADC pins of a PIC16F. I'd like to find chip that would let me do the same thing on the -15V rail, ie current sense resistor on the -15V line (so no resistor in ground path), output voltage from 0-5V referenced to common ground.

If anyone knows of any parts, please let me know! Thanks!

[mjb]

AFAIK you can only measure current draw by measuring the voltage drop across a known resistance.

[Amphiprion]

Right, I'm just trying to keep that resistance in series with the negative rail.

[sokoban]

Would this work at all for you?

http://www.thinkgeek.com/gadgets/electronic/7657/

[Amphiprion]

Nevermind guys, I found this app note:

http://www.maxim-ic.com/appnotes.cfm/an_pk/2011

Also I think I could just use a single supply instrumentation amp with a sense resistor on each rail. Hmm..