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bq24232H - Is additional battery protection required to pass UL safety requirements?

Mike Boos
Prodigy 20 points
Other Parts Discussed in Thread: BQ24232H

Hi,

I have designed in a bq24232H to charge a single Li-Ion cell rated at 210mA by Samsung. The design is for a wearable product in the form of a wristband. What I need to find out is if the battery requires additional protection, such as the bq29703, that would provide over/under voltage & over current protection (that the bq24232H lacks) in order to pass a UL safety certification for a wearable device. The application circuit on pg. 23 & 24 shows the battery without any additional protection circuit. The battery is fully encapsulated in the wrist band, and is not accessible by the user nor is it capable of being replaced. I would appreciate any comments on the necessity for additional battery protection.

Thanks, Mike Boos

  • 0
    TI__Expert 7730 points
    bq24232H does not have over voltage/current protection. It has a bat_short threshold at 1.8V below which it will stop supplementing current to output. Plus, it has back-to-back FETs internally to prevent the reverse current from Battery to input, however, it does not protect the battery against reverse polarity.

    Thanks,
    Wenjia
  • 0 in reply to Wenjia Liu
    Prodigy 20 points

    Thank-you for your comments, but I'm trying to find out if by using the bq24232H without any additional protection circuitry for the Li-Ion battery, would this be sufficient to pass a UL safety spec.

    Thanks, Mike

  • 0 in reply to Mike Boos
    TI__Expert 7730 points
    I don't know much details about what is included in the UL safety spec test. I suppose it is a system level spec that you have to pass with your overall architecture so I don't think we can guarantee it only from the charger perspective.
    With that said, I have not heard any comments about the performance of the charger is preventing the system from passing any safety spec.

    Thanks,
    Wenjia