INA226: INA226

user5737633

Part Number: INA226

dear ：

we use INA226 to measure about 15A to 20A current， what value Rshunt you suggest？ what is the minimum value we can use ，is there any limitation？

over 6 years ago

0 kai klaas69 over 6 years ago

Guru 140200 points

The maximum shunt is 81.92mV / 20A = 4.096mR. Decreasing the shunt will increase the error due to the input offset voltage (shunt offset voltage).

Kai

0 Guang Zhou over 6 years ago in reply to kai klaas69

TI__Mastermind 34250 points

Hi,

You might want to check out this video that goes over how to choose the shunt resistor:

https://training.ti.com/getting-started-current-sense-amplifiers-session-4-how-choose-appropriate-shunt-resistor?cu=456802

Regards, Guang

0 user5737633 over 6 years ago in reply to kai klaas69

Prodigy 20 points

due to voltage drop & ，we want to use as samll Rshunt as possible， please advise with 20A current，which value is batter？

0 Guang Zhou over 6 years ago in reply to user5737633

TI__Mastermind 34250 points

Hi,

Did you find the video helpful in answering your questions?

The system error versus your tolerance for the minimum detectable current determines the lowest shunt you can use.

Here is a rough hypothetical example – say the total error is 50uV referred to input and the minimum current you need to measure is 1A. And the maximum error you can tolerate is 10% at this current level. Then the shunt voltage would need to be at least 500uV. This voltage dictates the shunt resistance to be 0.5mOhm minimum. After selecting a shunt that satisfies this condition, check to see if the input is over range at the max current level. In this case 0.5*20=10mV, it is OK. Also compare this minimum value to your target max acceptable value.

You can adapt the above process to your specific current range and tolerance. In general it is better to choose a shunt as large as possible from pure measurement stand point of view.

Regards, Guang

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INA226: INA226