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INA196: INA196, ucd90990, lm5069 current sensing with a shared shunt?

Christian Doiber
Prodigy 20 points
Part Number: INA196
Other Parts Discussed in Thread: LM5069, , INA303, INA302, INA301

I want to know if it is possible to share the shunt of the LM5069 for an inrush current protection with an INA to monitor the used acutal current.

i do not like to use a second shunt, as it needs more space and cost.

is there some valid argument against it?

  • 0
    Guru 140200 points
    Hi Christian,

    should work, provided the input bias current of LM5069 is not disturbing your current measurement with the INA196.

    Kai
  • 0
    TI__Genius 17100 points

    Hi Christian,

    It’s possible to share the shunt of a current controller with a current sensor like the LM5069 and INA196. The only tradeoff is accuracy of the measurement depending on the input resistances of both devices and the shunt resistance used for sensing.

    A lower shunt resistor will yield more accurate results and high input resistances of the sensors will additionally help. Since the input bias current of the LM5069 is more than an order of magnitude greater than the INA196’s, the measurement error could be on the milliamps scale.

    The INA301, INA302, and INA303 operate at a lower common-mode voltage, but offer current sensing with overcurrent protection in one package.

    Thank you for using TI products, if you’d like additional details please reply!

     

    Regards,
    Manuel Chavez