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BQ40Z50-R1: Maximum load for the charge pump

Predrag Pejic
Prodigy 75 points
Part Number: BQ40Z50-R1


For the application we are designing the BMS using BQ40Z50-R1 for, we are having a resistor divider as a feedback from the DSG output of the IC(BQ_DSG connects to actual BQ DSG pin)

Through experimenting, we have realized that the value of 30k is too low and the gauge won't start. Using the value of 900k works though(total value for R40+R42).

We would like to make sure before we do extensive testing what is the limit on the maximum current BQ's internal charge pump could provide as the values are not given in the datasheet.

Thanks

  • 0
    TI__Guru 57697 points

    Hello Predrag,

    The DSG pin is used to drive a FET. I would recommend using the EVM as a reference for implementation.

    Datasheet section 7.18 Electrical Characteristics: CHG, DSG FET Drive shows characteristics with typical values.

    Refer section 9.2.2.3.3 PACK and FET Control and See Figure 33 for correct use.