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BQ40Z60: bq40z60 general questions

Part Number: BQ40Z60
Other Parts Discussed in Thread: BQSTUDIO

Here are several questions that I have regarding bring up of a custom PCB using the bq40z60.

1) Is it necessary to do a learning cycle in order to get the charging section to work?

2) I have the same problem as others in this forum with the ACLW bit toggling all the time and charging either not starting or stopping all together only to start again if I raise the adaptor voltage.

a. Once I raise the adaptor voltage it will start again and again stop unless I raise the voltage again.

3) I've seen mention of setting the charging voltage threshold within bqStudio but have not seen that variable

4) I'd like to be able to set parameters within data flash in order to get charging to work at a constant current and stop at 4.2V/Cell, I have a 3s4p battery pack setup with all the correct jumpers necessary for that.

  • Hi Frank,

    1. No
    2. What voltage are you using for input?
    3. Do you mean charge termination voltage?
    4. its in advanced charging algorithm in data memory

    Best,

  • The charging voltage starts off at 16V then I have to ramp it up to 26V in steps when the charging stops and each prior step

    This forum topic "BQ40Z60: ACLW toggling during charging" talks about a voltage register.

    I don't see that in the bqStudio anywhere. I attached a screen shot of the my bqStudio, but I don't see it in the original message.

    So why do I have to continually up the charging voltage? Where is the theshold set for that.

    What exactly is the ACLW bit looking at to determine itself?

    Charging voltage = 16800mv (4200mv per cell)

    Minimum Output Voltage = 610 mV × (1 + 332000 / 26100) = 8369

    Voltage Resolution = 8396 / 256 = 32.69

    Voltage Register = (16800 – 8369) / 32 = 263.4, this is higher than the allowed value of 256

  • Hi Frank,

    I have not encountered this issue on our EVM, anything over 15V should be ok. May be something else going on here.

    Can you attach logs showing behavior and schematic.

    Thanks,