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BQ25731: Multi chemistry not mentioned on datasheet

Kim Yue
Prodigy 335 points
Part Number: BQ25731
Other Parts Discussed in Thread: BQ25703A

Tool/software:

Hi Team,

Under BQ25731 product folder features, it mentions support multiple cell chemistry but this information is missing on the datasheet.

Customer needs this USB charger to support both Lithium-ion and NIMH. Is there any other literature customer can refer to? 

Thanks,

Kim Yue

  • +1
    TI__Mastermind 32745 points

    Hi, Kim,

    We mentioned it in the BQ25703A datasheet. In principle, our buck-boost chargers do not check for battery chemistry, they perform the charge function regardless of the battery type. They are high efficiency solutions for multi-chemistry chargers. 

    Regards,

    Tiger

  • 0 in reply to Tiger Zhou
    TI__Prodigy 335 points

    Hi Tiger,

    Thank you for your reply. Could you please help with questions below, or suggest other parts? Thank you!

    While the description mentions NiMH compatibility, I’m fairly certain that the BQ25731 lacks the ability to perform key end-of-charge detection methods such as:

    -Delta-V detection,
    -Temperature rise rate, or
    -Time-based cut-off.


    These are critical features for a proper NiMH charger IC to prevent overcharging and prolong the life of the cells. Without them, the chip will overcharge the pack, leading to gradual damage to the cells.

    If you’re sure it supports NiMH, could you please provide an application circuit demonstrating how the BQ25731 can be used to safely charge a NiMH pack from a USB power source?

    Best regards,

    Kim Yue

  • 0 in reply to Kim Yue
    TI__Mastermind 32745 points

    It looks you are looking for a dedicated NiMH charger.  Try the product selector below. 

    www.ti.com/.../products.html

  • 0 in reply to Tiger Zhou
    TI__Prodigy 335 points

    Hi Tiger,

    Thank you for your reply. Actually customer is looking for charger to support both Lithium-ion and NIMH. Does the key end-of-charge detection methods only available on dedicated NiMH chargers? Not available on buck-boost chargers that supports multiple cell chemistry?

    Thanks,

    Kim Yue

  • +1 in reply to Kim Yue
    TI__Mastermind 32745 points

    HI, Kim,

    The key end-of-charge detection methods may be available on dedicated NiMH chargers, but not available on buck-boost chargers that supports multiple cell chemistry.

    Regards,

    Tiger