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BQ4050EVM-561: Not Delivering Expected Charging Current to Battery

Vinayak Sankar
Prodigy 50 points
Part Number: BQ4050EVM-561
Other Parts Discussed in Thread: BQ25700A, BQ4050, BQSTUDIO

Tool/software:

I have set up the BQ4050EVM and BQ25700A EVM boards in the following manner:

I have configured the BQ4050 parameters according to my battery specifications and carried out voltage and temperature calibrations. I have not performed the CEDV calibration since fuel gauge accuracy over temperature is not a priority for me at the moment.

The batteries I am using are currently discharged, and I am trying to charge them using this setup, and then discharge, to get the fixed EDV coefficients. There is no load connected to the VSYS pin on the BQ25700EVM.

When reading the ChargeCurrent register from the BQ25700EVM using BQStudio, I see a charging current of 1344 mA. However, when measuring the current using an ammeter placed between VBAT (battery system) and the fuel gauge, I only observe 89 mA.

Why am I not seeing the expected 1344 mA charging current? Am I missing any configuration settings?

  • 0
    TI__Mastermind 28480 points

    HI Vinayak,

    Can you please confirm that the CHG pin is producing the correct amount of voltage to close the charge FET at this time?

    Also, can you please confirm whether any current calibration has been completed along with what is being seen across the sense resistor at this time?

    Regards,

    Anthony

  • 0 in reply to Anthony
    Prodigy 50 points

    Hi Anthony,


    I can see 20V on the CHG pin test point given on the EVM Board.

    Current Calibration has not been done, however there is not much deviation in current reported by the BQ4050 as observed on the BQStudio (In the Register Section)

  • 0 in reply to Vinayak Sankar
    TI__Mastermind 28480 points

    Hi Vinayak,

    Thank you for clarifying, it seems like the charge FET is active and is expecting a charge current to be passed, however this is not being received. If the charger is not producing the correct current, then I would have the charger team check the current configuration of the charger. This can be done by posting a new thread with BQ25700A as the Part Number.

    Regards,

    Anthony

  • 0 in reply to Anthony
    Prodigy 50 points

    Hi Anthony, Thanks for the suggestion.

    I shall check with the charger team