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INA169: INA169 - Separate references for supply circuit and load circuit

Antonio Maria Agostinelli
Prodigy 10 points
Part Number: INA169
Other Parts Discussed in Thread: AMC1300, AMC1302, AMC1200

Hello, I am designing a high-side current sensing circuit using INA169.

Is it possible to power INA 169 using a supply circuit with a reference that is galvanically isolated from the load circuit reference?

I am asking this question because figure 9 on page 12 of the datasheet states that "V+ power can be common or independent of load supply", but it does not specify wheter the two supplies can have two separate references, or if they must share the same reference.

Datasheet: https://www.ti.com/lit/ds/symlink/ina169.pdf

Thank you in advance,

Antonio

  • 0
    TI__Mastermind 26485 points

    Hello Antonio,

    Thank you for using the forum.  The Supply and output are not isolated.  VS cannot go above 75V from the GND pin and the output pin is limited to -.3V and 40V referenced to its output pin.

    You could increase the VCM of the input by floating the supply and using a high voltage BJT as seen in this circuit .  If larger isolation is required I would guide you to one of Isolation Amplifiers we have.   Some are designed with isolated current sensing in mind like the AMC1200, AMC1300, AMC1302 and others.

    If you think the Isolation Amplifiers is you path let me know and I will ask an expert from those products to help.