INA239: Damaged INA239 current sensor?

Douglas Lee

Part Number: INA239
Other Parts Discussed in Thread: INA168

Tool/software:

Hello!

I have ordered and integrated two INA239 current sensors to measure the power of my system. I am using a 1mOhm shunt resistor with both the sensors. I believe one of the two sensors are damaged or the one of the shunt resistors are shorted through. I have come to this conclusion because in my software I am able to communicate with both the sensors using SPI and read the correct manufacture ID. The manufacture ID I get from both of the sensors are 84 73 in decimal and TI in ASCII. I can also use my software to read the shunt voltage as well. Only one of them reads a shunt voltage while the other does not. The one that I suspect is damaged is the sensor that usually reads higher power (up to 300 watts).

They were working good before until the system had some electrical issues, and now one of them is not reading.

Let me know what other options that are possible.

Thanks, D

over 1 year ago

0 Douglas Lee over 1 year ago

Prodigy 40 points

This is the datasheet of the INA239. INA239 85-V, 16-Bit, High-Precision Power Monitor With SPI Interface datasheet (Rev. A) (ti.com)

0 Mallika Senthil over 1 year ago

TI__Expert 8970 points

Hi Douglas,

Douglas Lee said:
The manufacture ID I get from both of the sensors are 84 73 in decimal and TI in ASCII

The Manufacturer ID should have ben 5449h, 21577 in decimal. I suspect some errors in your code. Also, if you're not reading a shunt voltage, then I'd check whether the shunt resistor is shorted or not.

If the above checks still don't solve the issue, I'd recommend swapping out the old INA239 for new INA239s and retesting.

Best,
Mallika Senthil

0 Douglas Lee over 1 year ago in reply to Mallika Senthil

Prodigy 40 points

Hi Mallika,

thanks for the quick reply.

If that is the Manufacturer ID then how does that read back "TI" in ASCII?

I would like to make sure before I replace the INA239 that I have because it is a small IC on my board. Which makes it hard to take off and on by hand.

Thank you, D

0 Mallika Senthil over 1 year ago in reply to Douglas Lee

TI__Expert 8970 points

Hi Douglas,

You're right, I read your decimal value as 8473 and not as 84 73.
84 73 in decimal is the same as 5449 in hex, you're getting the correct address, here are a few similar E2E posts that you could use to ensure your code is correct. The next course of action would be to check if the resistor is shorted and then to replace the INA239s. If the issue still persists, please feel free to follow-up.

https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1074352/ina229-ina229-current-sensor-reading-wrong-manufacturer-id

https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1131138/ina229-ina229-current-sensor-reading-manufacture-id

https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1249058/ina229-ina229-spi

Best,
Mallika Senthil

0 Douglas Lee over 1 year ago in reply to Mallika Senthil

Prodigy 40 points

Thanks Mallika for the update. I should have been more clear on how the value showed up while typing this online. In the datasheet on page 32, table 8-3 states that the current max is 10 amps. Is this the max current of the chip or is this just a scenario?

0 Mallika Senthil over 1 year ago in reply to Douglas Lee

TI__Expert 8970 points

Hi Douglas,

The Imax=10A is specific to the application mentioned in the datasheet.

Best,
Mallika Senthil

0 Zain Nasir over 1 year ago

Expert 1430 points

You can try to swap the positions of the two INA239 sensors. If the problem moves with the sensor, it is likely that the sensor is damaged. If the problem stays in the same position, it could be an issue with the shunt resistor or the connections. Use a multimeter to measure the resistance of the shunt resistors directly. Verify that both resistors have the same resistance value (1 mOhm). A significant difference in resistance values indicates a problem with the shunt resistor. You can also try INA168 if your application supports it. www.pcbway.com/.../INA168_Current_senser_module.html

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INA239: Damaged INA239 current sensor?