What is the best current sensor IC for measuring a voltage source (30 V) and 6 A - Page 1
Forum section: electronics / general

author: Jony_1
author_rank: Newbie
timestamp: January 28, 2023, 03:37:03 am
content: Hello guys,I need the smallest current sensor IC (because I don't have much space on my PCB) that has these specifications:Has good isolation (more than 500 V)Works with 3.3 V (I need to connect to an MCU)Measures currents up to 6 A.I will be grateful if you could introduce me to some ICs that you worked with.

author: Psi
author_rank: Super Contributor
timestamp: January 28, 2023, 03:49:38 am
content: Does it need the current to pass through the chip, or use external sense resistor?

author: Jony_1
author_rank: Newbie
timestamp: January 28, 2023, 04:49:53 am
content: Thank you Psi for your comment. Both strategies work fine for me.

author: bdunham7
author_rank: Super Contributor
timestamp: January 28, 2023, 05:00:36 am
content: https://www.allegromicro.com/-/media/files/datasheets/acs71240-datasheet.pdf

author: eutectique
author_rank: Frequent Contributor
timestamp: January 28, 2023, 05:19:28 pm
content: TI has a range of isolated amplifiers for current sensing:https://www.ti.com/isolation/isolated-amplifiers/products.html#p1694=Current%20sensing

author: Psi
author_rank: Super Contributor
timestamp: January 30, 2023, 12:17:15 am
content: Many options if its a one-off and you don't care too much about price.HALL current sensors are probably the best for getting isolation out of the box, but they can get expensive if you want a module.The IC versions are cheaper.They can be PCB mount or external boxes, and where the current sense is either a ring you place your wire through, or may have the current path built in. Sometimes they come with multiple current paths that you can wire up in series/parallel to change the current detection range of the sensor. Some just look like a normal IC but you pass the current though some of the pins on one side.They also make odd ones that sense the current on a pcb track going under the IC.One downside of hall sensors is they are usually not that accurate, or rather the accurate ones can get expensive.Also the accuracy of your ADC comes into play too.https://www.digikey.co.nz/en/products/detail/broadcom-limited/ACHS-7121-000E/9178254

author: TomS_
author_rank: Frequent Contributor
timestamp: January 30, 2023, 09:25:10 pm
content: I used a couple of Microchip PAC1952's in a recent project and they seem to work pretty well for me.Current and voltage measurements are more or less arbitrary because you can always use resistor dividers to scale things down for the hardware and then multiply back up in software.

author: betocool
author_rank: Regular Contributor
timestamp: February 01, 2023, 12:16:33 pm
content: I like the LTC2992, if you can get it!I've used it in multiple designs over the years, have a read through the datasheet. We measured up to 25A using a very small sense resistor.Cheers,Alberto

author: Psi
author_rank: Super Contributor
timestamp: February 02, 2023, 10:39:25 pm
content: OP said he wants 500V isolation, so I think it needs to be HALL or transformer based.I've never seen a Isense amp chip that can do 500V on the sense lines.