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INA181: Can INA181 be applied to higher bus voltage systems?

Sang-il Nam
Expert 2260 points
Part Number: INA181

Hi,

The common-mode voltage of INA181 is 26V max.

If this product is used for low-side sensing, can it be applied to higher bus voltage systems?

(For example, 48V or 60V or Higher DC-Bus voltage motor control system)

Thanks.

  • 0
    TI__Expert 4915 points

    As long as the device supply shares the same ground as the DC-LINK system and the supply is kept within the allowable limits, the configuration below can be used, provided the voltage across Rsense is within the limits supported by the device

  • 0 in reply to Carlos Silva85
    Expert 2260 points
    First of all, thank you for your quick answer.

    Does your answer mean that the "Power Supply" in the picture should not exceed the maximum value supported by the device? (i.e. 26V MAX)
    Or, Is it possible to use as low-side sensing even if the 'Power Supply' is 48V or higher?

    Best Regards,
    NAM, Sangil
  • 0 in reply to Sang-il Nam
    TI__Expert 4915 points

    Hi Sangil,

    It is possible to use a low side configuration independently of the power supply voltage. The device itself will require its own supply with a range of 2.7 to 5.5V.

    The 26V limitation only applies to the bus voltage where high side sensing is employed.

  • 0 in reply to Sang-il Nam
    TI__Prodigy 85 points

    Sangil,

    The Power Supply can exceed the 26V if you are doing low-side sensing because the common mode voltage in this case is close to the ground potential (0V).

  • 0 in reply to Motaz Khader
    TI__Expert 4915 points

    Just to clarify, in case my previous answer generated any questions, yes the device can measure currents on a DC-LINK system of any given voltage, assuming it is

    a) Used on the low side configuration
    b) The voltage developed across the Rsense resistor doesn't exceed the maximum values allowed by the device for the IN- and IN+ inputs, for example, in case of large inrush, pre-charge or a temporary inrush caused by a brownout, in which case a clamping mechanism should be employed.
    c) The device has its own power supply, referenced to the system ground, not exceeding 26V 5.5V, as per datasheet spec.

  • 0 in reply to Carlos Silva85
    Expert 2260 points
    Thank you for answer. It was a great help.