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Battery Charging and Discharging current measurement using LPV521

Other Parts Discussed in Thread: LPV521, BQ24295


I want to measure battery charging and discharging current using series small value resistor and LPV521.

Suggest circuit interface using LPV521 to measure charging and discharging current using single series resistor.

  • Hi Sunil,

    You are going to have to give us more details.

    What is the battery voltage? What is the expected current loads? How much load voltage loss can you tolerate? Is the amplifier powered from the same battery or a different supply?

    And why are you choosing our lowest power op-amp? I assume it is to save power (but that also creates some design compromises).


  • Hi Paul,

    My battery voltage is 4.2V max. Battery charging current is 3A max and discharging current is 1.5A max using BQ24295 IC.

    Load voltage loss should not be more than 30mV.

    When battery is charging, amplifier is powered through main source supply and during battery discharging, amplifier is powered through battery supply.

    I want to measure current at High side current sensing resistor. So, Main source supply ground and battery ground are same.

    Of course, I have chosen LPV521 for power saving purpose during discharge mode.

    Let me know what are the design compromises/limitations with LPV521?