INA226 measurement accuracy

na na78

Could you check if the following my considerations is OK?

We can set the Current_LSB using Maximum Expected Current.

If Rshunt = 0.1mOhm, the maximum expected current that can be accepted by IC is 800A (because the shunt voltage input range is from -81mV to 80mV).

In this case, Current_LSB = 800/2^15 = 0.0244=24.4mA/bit.
(CAL = 0.00512/(Current_LSB x Rshunt) = 2098)

If the maximum expected current is set as 400A, result in Current_LSB = 12.2mA/bit.

The measurement accuracy improves as minimizing the maximum expected current, is it correct?

BestRegards

over 9 years ago

0 Mayrim Verdejo over 9 years ago

TI__Genius 15770 points

Hi na na78,

Your calculations are correct. The measurement accuracy of the ADC won't improve though, you will just have better resolution.

800A & 400A is a lot! You mind sharing your application information?

Regards

0 na na78 over 9 years ago in reply to Mayrim Verdejo

Guru 16770 points

Hi Mayrim

Thank you for your reply.

We assume that current measurement of car battery cells.
But our question was just example. We wanted to confirm our understanding.

BestRegards

0 na na78 over 9 years ago in reply to na na78

Guru 16770 points

Hi Mayrim

I'm sorry, can you confirm the following?

Even If we have better resolution, it doesn't influence to offset error, does it?

BestRegards

Amplifiers

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INA226 measurement accuracy