BQ20Z70-V160: BQ20Z75 current calibration

There must be something wrong on your board if there's such a large difference in current measurement between charge and discharge current. The gauge measures current indirectly by measuring the voltage drop over a sense resistor so if you calibrate for (=calculate a CC Gain parameter, which the gauge uses to convert the coulomb counter ADC result) a positive voltage drop of 30mA * Rsense for a charging current then a negative voltage drop of -30mA * Rsense will cause a -30mA result.

If you notice a massive difference in accuracy between charge and discharge currents, then chances are that something causes an incorrect voltage drop measured on SRN and SRP over the sense resistor in your system.

Hi Dominik,

    when i use a new board to calibrate the current, once the pack is in standby mode, no charge and no discharge, the current is about -12mA.

    how to revise the board with 0 current when there is no discharge and charge？

Please measure the voltage across the sense resistor to make 100% sure that there is no current. While there will be some offset error (if the voltage across the sense resistor is zero), it won't be so high to produce a 12mA erroneous current.

Hi Dominik,

   what's normal current range when there is no charge and no discharge?