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BQ25886: Dynamically changing the VSET resistor

Part Number: BQ25886
Other Parts Discussed in Thread: BQ25883, BQ25882

Hi,
the BQ25886 has a pin called "VSET" to set battery charge voltage. Is it possible to replace the recommended programming resistor with a digital potentiometer (that is powered from VBUS). The idea of this setup is to have a possibility to program the battery charge voltage from a microprocessor and then store this setup in a NV memory. 

My concern is that the BQ25886 could probe the programming resistor only during power up (when the battery is inserted). At that time Vbus is not present and as a result of this the programming resitor is invalid. 

(Using the BQ25883 is no option for our application because we need the OTG pin)

Thank you for your help!

Best regards
Reto

  • Hello Reto,

    Yes that should work fine, the charger will react according to whatever resistance is on that pin.

    The BQ25882 has very similar features including OTG and I2C. The differences are the STAT pin and package type.

    Sincerely,

    Wyatt Keller