current sense - Page 1
Forum section: electronics / projects

author: electros6
author_rank: Regular Contributor
timestamp: September 13, 2013, 10:11:34 am
content: Hi guys ,I am working on a project where I want to implement high side current sense on a 48V dc supply rail. Please guide me

author: TerminalJack505
author_rank: Super Contributor
timestamp: September 13, 2013, 10:25:35 am
content: I'd use one of the ICs dedicated for this. TI'sINA169, for example.

author: tszaboo
author_rank: Super Contributor
timestamp: September 13, 2013, 11:28:49 am
content: Self advertising:http://nandblog.com/current-shunt-monitors/I suggest the INA19x series.

author: Andreas
author_rank: Super Contributor
timestamp: September 13, 2013, 07:04:54 pm
content: LTC6101 or LTC6101HVWith best regardsAndreas

author: tree
author_rank: Regular Contributor
timestamp: September 13, 2013, 10:31:38 pm
content: MAX4372.I used that to build a battery monitor when I was an intern at NASA. One of the high ranking EEs advised that we use that chip because it's a legacy component (i.e. flew successfully on previous missions)

author: tszaboo
author_rank: Super Contributor
timestamp: September 13, 2013, 10:50:02 pm
content: Quote from: tree on September 13, 2013, 10:31:38 pm... is a 28V part, which will fry with 48V.

author: tree
author_rank: Regular Contributor
timestamp: September 13, 2013, 10:52:01 pm
content: Quote from: NANDBlog on September 13, 2013, 10:50:02 pmI thought he meant he has to monitor current on a 48V rail. (i.e. not necessarily running the chip on 48V)EDIT: Never mind. common mode is limited to 28V.

author: SeanB
author_rank: Super Contributor
timestamp: September 14, 2013, 05:53:47 am
content: http://www.analog.com/en/circuits-from-the-lab/CN0218/vc.htmlJust released as a current monitor with a 500V CMMR range.....Even has a video on the channel.

author: nctnico
author_rank: Super Contributor
timestamp: September 14, 2013, 10:02:53 am
content: This is a very expensive solution. Its better to use a hall sensor from Allegro if you need high voltage isolation. The Adum5xxx parts look nice though. I've used one to isolate a circuit to meaure the mains voltage.

author: fcb
author_rank: Super Contributor
timestamp: September 14, 2013, 10:20:36 am
content: To some extent it will depend on what bandwidth, accuracy, current & calibration you want.The gold standard would of-course be a differential amplifier across a nice little low-tempco 4 terminal shunt. Perhaps you can afford a little current drain from both sides, in which case you could use potential dividers to make that 48v a bit easier to interface to.However at 48v (4 lead-acids, telecoms 36-72v, mic phantom powering, PoE, PSU, traction...?) we would need to know a little bit more to really advise.*NOTE/RANT* - when I started out in electronics MAXIM used to send out these little blue & white pamphlet/magazines (perhaps they still do?). I often used to design using stuff from them - same goes from National/TI/ST, even when the BOM wasn't an issue, the sourcing of these parts was always a headache. Nowadays I'm loathed to change from designing in LM358/NE5532/TL072/LM339/ULN2803A, etc unless absolutely necessary.**THAT SAID** - I love the Allegro ACS parts that nctnico talks of. Just finished a design job with them in - real pleasure to do.