INA226: The solution of current measurement for high voltage on high side application

user5277258

Part Number: INA226
Other Parts Discussed in Thread: AMC1300, ISO1541, INA220, INA233

Dear Sirs:

My product needs to use current measurement in high voltage environment(ex:600V).

And I want to place INA226 in High Side to measure shunt resistor.(0.3mohm 1W 10pcs in parallel for 580A, and the error is limited under 1%)

But according to the INA226 SPEC, the common voltage restrict is 40 Volt.

Is there any problem to place an isolated OPA between INA226 and shunt resistor?

Do you have any suggested isolated OPA to match INA226?

Or other better solution for this case?

My percision still needs to be high like 16bits or 32bits.

Thanks~

over 5 years ago

0 Peter Iliya over 5 years ago

TI__Mastermind 32395 points

Hello valued TI customer,

You could go to the isolated amplifiers product page and search for isolated current sensing amplifiers on this page: http://www.ti.com/isolation/isolated-amplifiers/products.html

I find the following amplifier to compare: http://www.ti.com/assets/js/compareParts/compare.html?familyId=512&parts=AMC1302,AMC1300,AMC1301,AMC1100,AMC1200&cols=o1,p1034,p750,p751,p3045min,p3300max,p767typ,p768max,p2214typ,p754max,p3265typ,p1498,p1192,p753max,p2954,p1811,p1130&lang=en

With these isolated amplifiers you will not need the INA226 anymore, but rather just an ADC. However, you will need to provide a Zener diode to generate the regulating 5V supply for the high-voltage side of the amp (this is shown in the AMC1300 datasheet). Additionally, these are analog-output devices so you will need an ADC to convert the low-level output voltage.

The other option is to use a regular digital current/power monitor (such as INA226, INA233, or INA220) and provide the same Zener regulating voltage drop that floats with the 600V rail. In addition to this, you could use a digital isolater (such as the ISO1541) to level-shift the digital output from 600V to GND. See these reference designs for detailed design information.

40 V to 400 V Uni-directional Current/Voltage/Power Monitoring Reference Design

http://www.ti.com/lit/ug/tidu849/tidu849.pdf

High-voltage, high-side floating current sensing circuit using current output, current sense amplifier

http://www.ti.com/lit/an/sboa295/sboa295.pdf

–48-V Telecom Current, Voltage, and Power Sense With Isolation Reference Design

http://www.ti.com/lit/ug/tidu361a/tidu361a.pdf

Sincerely,

Peter

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INA226: The solution of current measurement for high voltage on high side application