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INA240: High common mode voltage. 230V

Luuk Grefte
Prodigy 20 points
Part Number: INA240
Other Parts Discussed in Thread: TMDSHVMTRINSPIN, INA138

Hi TI,

I am using your InstaSpin technology and now want to sense motor current. As TI advertises really by doing this inline(with several advantages), the disadvantage is the high common mode voltage.

As the INA240 only can handle a common mode voltage of 80V, 230V is to high. Is using a floating current sense circuit the best solution here? http://www.ti.com/lit/an/sboa295/sboa295.pdf

Or is there a better solution? (just using an amplifier?). 

I btw also asked for the schematics for the TMDSHVMTRINSPIN(as this is standing on my desk, and it should have something implemented to do this).

Thank you

  • 0
    TI__Mastermind 33410 points

    Hi Luuk,

    The INA138 floating circuit will not work well as an inline current sensor, because it is unidirectional. There are circuit examples in the datasheet for bidirectional current sensing. You might be able to adapt them similarly into floating ones.

    However it is probably a cleaner solution to start with isolation amplifiers to handle the high voltage. Here are a couple of reference designs:

    TIDA-01541

    TIDA-010025

    Regards, Guang