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INA181: Low-Side Sensing 3 Phase Motor Control Application

BenK
Prodigy 60 points
Part Number: INA181
Other Parts Discussed in Thread: INA240, INA241B, INA241A

Dear E2E Community,

we have successfully developed a motor driver incorporating inline current sensing using an INA240A1 current sensing amplifier and we are highly satisfied with the performance of the current sense circuit, particularly in applications demanding high dynamic and precise current sensing.

Currently, we are working towards designing a more cost-effective solution that utilizes low-side current sensing. Our solution operates with a bus voltage of 48V and demands a continuous current range of 50A, with peak currents reaching up to 100A. We would appreciate your insights on whether the INA181A1 is a suitable component for this motor driver project.

Thank you in advance for your assistance.

Kind regards,

Ben

  • +1
    TI__Mastermind 29810 points

    Ben,

    The biggest issue we have seen is when the spikes in voltage at the input any INA go below the Absolute max rating.  This happens during the switching and causes issue damage to the device if the inputs go below Absolute max.  

    If you will not see these spikes then I think the INA181 could work for you.  If you do see the spikes you would either have to mitigate them or find an alternative solution.

    Alternative solutions all cost more.  Either getting another current sense amplifier that can go below GND as the -VCM.  (cost adder).  Or go high side and have a current sense amplifier that goes above the 48V plus the extra headroom needed for the spikes.(cost adder).

    Let me know what path you are thinking.

    Regards,
    Javier

  • 0 in reply to Javier Contreras4
    Prodigy 60 points

    Hello Javier,

    I appreciate your prompt response. Ensuring a maximum voltage drop of -0.2V below ground seems to pose a significant challenge. As a result, we have decided to maintain our current choice of using the INA240.

    Once again, thank you for your assistance.

    Kind regards, Ben

  • 0 in reply to BenK
    TI__Mastermind 29810 points

    Hello Ben,

    Please also take a look at the INA241A and INA241B.