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BQ2961: Part selection in case of using LiFePO4 battery

Chase Jeong
Mastermind 7365 points
Part Number: BQ2961
Other Parts Discussed in Thread: BQ4050, BQ2969, BQ2969T

Tool/software:

Dear TI experts,

My customer considers BQ4050 and BQ2961 for their next project.

The problem is, recommended overvoltage protector in BQ4050 EVM is BQ296103, which OVP is 4.50V.

I think it is for Li-ion battery, not for LiFePO4.

Could you recommend overvoltage protector which can work with LiFePO4?

Best regards,

Chase

  • 0
    TI__Genius 17755 points

    Hello Chase,

    Our devices are not dependent on battery type, only the voltages seen. The BQ2961xx family can be programmed by TI to have an OVP as low as 3.85V to as high as 4.60V. What OVP threshold range are you looking for? We have several other 2-4S protectors that may also be worth considering such as the BQ2969 or the BQ2969T. 

    Best Regards,
    Alexis

  • 0 in reply to Alexis_H
    Mastermind 7365 points

    Dear Alexis,

    Thank you for your support.

    My customer wants OVP value as 3.65V

    Could you recommend proper device?

    Best regards,

    Chase

  • 0 in reply to Chase Jeong
    TI__Genius 17755 points

    Hello Chase,

    The BQ2969 or BQ2969T family may be better suited for what you're looking for as they can be programmed to have an OVP as low as 3.5V. Please refer to the product pages I've shared above for those families. 

    Best Regards,
    Alexis

  • 0 in reply to Alexis_H
    Mastermind 7365 points

    Dear Alexis,

    Thank you for your support.

    I checked BQ2969 and BQ2969T datasheet and it says that OVP threshold is factory programmed.

    And I cannot find mass production part number for 3.65V OVP so far.

    Could you check it again? (RTM schedule, available samples for 3.65V OVP)

    Best regards,

    Chase

  • 0 in reply to Chase Jeong
    TI__Genius 17755 points

    Hello Chase,

    There needs to be a sufficient business case for TI to factory program the settings desired. Have you reached out to your TI sales representative about this? 

    Best Regards,
    Alexis

  • 0 in reply to Alexis_H
    Mastermind 7365 points

    Dear Alexis,

    Thank you for your support.

    The application is external battery pack for Black Box(of car). Unfortunately the quantity is not great.

    One more question is, BQ4050 supports LIFePO4 battery but BQ2961 in BQ4050 EVM supports only Li-ion and Li-polymer battery, not LiFePO4.

    I think TI should recommend another way to replace BQ2961 for OVP of LiFePO4.

    Or, Is it okay to remove BQ2961 in the EVM so we can protect LiFePO battery from OVP using only BQ4050? Is it possible?

    Like I said the charging voltage of LiFePO4 battery is 3.65V. So my customer should run OVP near 3.65V.

    Please check this issue. Thanks.

    Best regards,

    Chase

  • 0 in reply to Chase Jeong
    Mastermind 7365 points

    Dear Alexis,

    Hope you had a good weekend.

    Please let me know if there are any updates about my last question. Thanks.

    Best regards,

    Chase

  • 0 in reply to Chase Jeong
    TI__Genius 17755 points

    Hello Chase,

    Thank you for your patience. The BQ2961xx in the BQ4050 EVM should be there as a secondary protector.

    Chase Jeong said:
    Or, Is it okay to remove BQ2961 in the EVM so we can protect LiFePO battery from OVP using only BQ4050? Is it possible?

    It should be possible to remove it as the BQ2961 is there as a secondary protector. Something to note, is that the BQ2961 from the EVM is connected to the FUSE. 

    Best Regards,
    Alexis

  • 0 in reply to Alexis_H
    Mastermind 7365 points

    Dear Alexis,

    Thank you for your support.

    I got your point.

    And could you check my additional question?

    "BQ4050 supports LIFePO4 battery but BQ2961 in BQ4050 EVM supports only Li-ion and Li-polymer battery, not LiFePO4.

    I think TI should recommend another way to replace BQ2961 for OVP of LiFePO4.

    Like I said the charging voltage of LiFePO4 battery is 3.65V. So my customer should run OVP near 3.65V."

    Please check this issue. Thanks.

    Best regards,

    Chase

  • 0 in reply to Chase Jeong
    TI__Genius 17755 points

    Hello Chase,

    Apologies for missing that. I did not realize that was also a question. We also have other 2 to 4S battery protectors such as the BQ2969 or BQ2969T that can have OVP be programmed to be as low as 3.6V. 

    There needs to be a sufficient business case to do so though. 

    Best Regards,
    Alexis