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Original question:

BQ20Z655-R1: Replacement Component / Risk of Obsolescence

BQ20Z655-R1: charging profile

Vincenzo Pizzolante
Mastermind 25456 points
Part Number: BQ20Z655-R1

hi,

there is the ChargingCurrent SMBus command that broadcasts the desired value of charging current.

We have seen that this command broadcasts values based on temperature and cell voltage measurements.

Is there any other way we can set the charging current value?

We would like that the battery is charged with 3A when charged from a specific kind of chargers and with 400mA when charged from chargers of other kind.

thansk a lot in advance

KR

Vincenzo

  • 0
    TI__Genius 11535 points

    Hi Vincenzo,

    Those are the only ways to set the charging current value. There is no way for the gauge to determine which charger is being used. Using such different charging currents might cause issues with setting up gauge protections and gauge learning.

    Best,

    Jessica

  • 0 in reply to Jessica H.
    TI__Mastermind 25456 points

    thanks a lot Jessica.

    Allow me few more questions:

    - I understand that the overvoltage thresholds for each of the temperature regions of operation for the IC are programmable at the data flash (1st Level Safety class, Voltage subclass 0). Is this correct?

    - The IC enters the SLEEP mode of operation when specific conditions are met. How can the SLEEP mode be forced by user?

    - Would it be possible to clarify the reasons why LFP cells are not being supported by the ICs under consideration? This is very important for us since LiFePO4 cells are now becoming very popular and are being offered by a lot of manufacturers. Is it possible to still use LFP by accepting some system limitations (lower accuracy, etc.)? Any additional information would help

    thanks a lot in advance

    have a great day

    KR

    Vincenzo

  • +1 in reply to Vincenzo Pizzolante
    TI__Genius 11535 points

    Hi Vincenzo,

    I apologize for the late response. 

    1. That is correct

    2. You can send the ManufacturerAccess Sleep() command but make sure the sleep bit in Operation Cfg A is set to 1

    3. The BQ20z655 uses an older version of the Impedance Track algorithm and the firmware was not designed to support LiFePO4. Since this is an older gauge we have stopped developing new firmware for this gauge. Since the algorithm was not designed to support that battery chemistry there will be lower accuracy and other potential gauging issues. With that said, if you are willing to take the risk you can try testing it out for yourself. Just be aware that there may be some unknown behaviors and the gauge might not perform the way it was designed to do so.

    Best,

    Jessica