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BQ76PL455A: bq76pl455a balance commands

Part Number: BQ76PL455A

Hello my friends
I want to make a battery management system with bq76pl455a. I'm reading the battery voltage. However, I could not find enough information about the balance. For example, I send {0x81, 0x00, 0x02, 0x20, 0x28, 0x84} commands. What kind of order should I send to balance the batteries?

  • Hi Enes,

    Have you read over section 7.3.7 Passive Balancing of the datasheet? It explains the steps in order and you just need to create those commands in your code. You will need to do more than just the read command you have above.

    Regards,

    Taylor


  • 4. I send {0x9A, 0x00, 0x00, 0x14, 0x00, 0x08, 0x5C, 0x38} to balance the battery, but there is no balance. What is the reason?

  • Hi Enes,

    Based on the frame you are sending, seems like you are trying to enable cell balancing on cell 4 only. 

    There are several steps you need to follow to get cell balancing working, on hardware and on software.

    First let's make sure that your circuit is correct. Please review the cell balancing circuit on the device datasheet, section 8.2.2.3 Passive Cell Balancing Circuit. Please also review sections 8.2.2.4 Balance FET and 8.2.2.5 Balance Resistor for details about selecting your balancing FET and balancing resistor. 

    Once you have ensured that you have the correct balancing circuit on your board, on software there are a few things you need to watch for. The details I provide below are described on section 7.3.7 Passive Balancing of the datasheet:

    • The squeeze function must be disabled for cell balancing to work ( TSTCONFIG[EQ_SQUEEZE_EN] = 0 )
    • If CB_CONFIG[BAL_CONTINUE] = 0 your balancing will stop whenever there is any type of fault in the device (with the exception of CUST_CKSUM_ERR). So, if you have any fault when you try to run your cell balancing it will stop. Please check that all your faults are cleared or you can also write CB_CONFIG[BAL_CONTINUE] = 1 to allow balancing to continue even if there is a fault
    • Then you can send the balancing command by writing to CBENBL register  

    Best regards,

    Leslie