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BQ40Z80: minimum Current Sense Resistor?

Bruce li
Genius 5580 points

Part Number: BQ40Z80

Dear  TI Expert,

My customer want to evaluate a project with maximum 90AH Capacity and 90A current. To finish this, they need to use the scaling function. Their question is what's the minimum Current Sense Resistor can be supported with Bq40z80? Even if they use 1mR Current Sense Resistor, when 90A current occur, there will be very big loss and heat, is there any other way to deal with the huge current sampling? Thanks a lot.

  • 0
    TI__Mastermind 42535 points
    Bruce,

    There's no other way to do it in this application. 1 mOhm is the minimum Rsns that we need for the gauge and is supported by it. Even if you were to implement a current bypass using external circuitry you are depending on the linearity of the external circuit or the regulating ability to scale the current across the sense resistor. This inherently introduces error in voltage measurement as you can't guarantee linearity across temperature and loads.

    So, this is the only way this gauge can do it.
  • 0 in reply to Batt
    Genius 5580 points
    Dear Batt,
    Got it, thanks a lot for your support.