INA219: Accuracy problem of INA219

Oliver Lin

Part Number: INA219

Hi team,

Customer feadback on their design, found some accuracy problem, please see below description, and some input to us on this modification, thank you.

In customer INA219’s R_shunt 0.25m ohm application, we use 0.25m ohm for sense current function. The INA219 will sense light load about 0.7A with R_filter (10 ohm) at no load, then customer change R_filter about 2 ohm to sense current and it can see about 0.2A.

So we change R_filter about 2 ohm, does it have any side effect or any risk?

9 months ago

0 Mohamed Hamida 9 months ago

TI__Expert 6602 points

Hi Oliver,

The best way to calculate potential error on our CSAs are through our error calculation tool. You can find there here: https://www.ti.com/tool/CS-AMPLIFIER-ERROR-TOOL. In this tool, you can fill the following section and see the potential error curve:

You can then play around with values and see how certain aspects effect the expected error. If you have any questions, please feel free to let me know.

Best,

Mohamed

0 Oliver Lin 9 months ago in reply to Mohamed Hamida

TI__Expert 3725 points

Hi Mohamed,

This chart does not include R_filter parameter, does that mean adjusting those resistors do not affect the accuracy? is that ok to put into 2ohm? Thank you.

0 Mohamed Hamida 9 months ago in reply to Oliver Lin

TI__Expert 6602 points

Hi Oliver,

As long as the R_filter is lower than 10ohms and match eachother, then it should not change accuracy.

Best,

Mohamed

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INA219: Accuracy problem of INA219