INA3221: Measuring alternating current

Kimmo Kemppainen

Part Number: INA3221

Is it possible to use INA3221 to measure alternating current when using TEC controller for peltier cooling? Voltage changes from -15V to +15V(polarity of voltage changes when heating or cooling), current stays under 5A. If not is there a chip that can do that?

over 1 year ago

0 Mohamed Hamida over 1 year ago

TI__Expert 6602 points

HI Kimmo,

The INA3221 does not have the capability of reaching -15V VCM. You could look into the LMP860x family of parts, which has the ability of reaching -22V VCM: https://www.ti.com/lit/ds/symlink/lmp8602-q1.pdf .A newer option would be our magnetic current sensors, which will allow for AC current sensing: https://www.ti.com/sensors/magnetic-sensors/products.html#-3=Hall-effect%20current%20sensors&

Please let me know if you have any further questions!

Best,

Mohamed

0 Kimmo Kemppainen over 1 year ago in reply to Mohamed Hamida

Prodigy 20 points

Hi Mohamed,

Thank you for your answer! Those magnetic current sensors sounds interesting. Is there a option with i²c communication? Any option with multiple channels like INA3221 has 3 channels?

0 Mohamed Hamida over 1 year ago in reply to Kimmo Kemppainen

TI__Expert 6602 points

Hi Kimmo,

Unfortunately we do not offer any magnetic current sensors that have built in digital communication. You can view all the features we offer in the product listings above. It should be able to filter by Vcm. Unfortunately we do not offer any multi-channel TMCS devices either. Please let me know if you have any further questions!

Best,

Mohamed

0 Kimmo Kemppainen over 1 year ago in reply to Mohamed Hamida

Prodigy 20 points

Hi,

Ok. Can you recommend some simple í2c adapter for those tmcs? Currently im using INA3221 but now i have to replace it because of this negative voltage issue.

0 Mohamed Hamida over 1 year ago in reply to Kimmo Kemppainen

TI__Expert 6602 points

Hi Kimmo,

You could use one of our ADCs that also include I2C communication located here: https://www.ti.com/data-converters/adc-circuit/products.html#1918=I2C&. There are many different factors to keep in mind when choosing an ADC. Please let me know if you have any questions

Best,

Mohamed

0 Kimmo Kemppainen over 1 year ago in reply to Mohamed Hamida

Prodigy 20 points

Hi Mohamed,

Just to make sure. If I connect INA3221 like in picture below. I use one channel to measure current of peltier element. Controller of peltier is this: PTC5K-CH 5 A Temperature Controller, Chassis Mount – Wavelength Electronics (teamwavelength.com)

Supply voltage for controller is 12Vdc. First 5min peltier is heating to reach right temperature. Then polarity of peltier is reversed to cool down peltier. Actually voltage does not go to negative side, only polarity is reversed. Is this connection possible? Or what that bidirectional text means in INA3221 datasheet?

0 Mohamed Hamida over 1 year ago in reply to Kimmo Kemppainen

TI__Expert 6602 points

Hi Kimmo,

Which bidirectional text do you mean in the datasheet? I wasn't able to find it. Also, the INA3221 allows for negative shunt values from -163.8mV to 163.8mV. The VBUS is read off of IN-, so switching the polarity would cause the 12V (If I understood correctly) to also switch, which would violate the 0 to 26V specification of the INA3221.

Best,

Mohamed

0 Kimmo Kemppainen over 1 year ago in reply to Mohamed Hamida

Prodigy 20 points

Hi Mohamed,

Thanks. I found older datasheet where that bidirectional text was mentioned. Newer version did not have that text anymore.

If I am precise there is no negative voltage. There is only +12V and GND in this device. When polarity changes +12V and GND changes their places.

It seems that there is no way to use this INA3221 in my case. Thank you, i have to find other solution.

Best regard,

Kimmo

0 Mohamed Hamida over 1 year ago in reply to Kimmo Kemppainen

TI__Expert 6602 points

Hi Kimmo,

In this case, bidirectional would mean the shunt value allowing from -163.8mV to 163.8mV. I believe they removed the word bidirectional as it began to be confusing, I'm sorry for the misconception. Please let me know if there's anything else I could assist you with.

Best,

Mohamed

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INA3221: Measuring alternating current