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BQ76905: Battery protection / monitor with functional safety output

Martin Sauer
Prodigy 150 points
Part Number: BQ76905
Other Parts Discussed in Thread: BQ76907

Tool/software:

Hi,
I'm looking for a device which can monitor / protect (cell balancing) a 2 series Li Ion cell akku pack. The device should a have an output if akku is good or bad or a failure occured which is SIL2. The device can programmed during functional test in mass production. But we don't use a microcontroller.

Can you recommend a device with this requirements?

Thank you for your help.

BR

martin

  • 0
    TI__Mastermind 24965 points

    Hi Martin,

    Our only monitor/balancer that can support 2s is the BQ76905. This is a programmable device, but cannot be OTPed by the user. If the default settings work for your application, then you can use it as a standalone part.

    We are able to set the default settings in the factory, but it requires a significant enough business case in order to warrant the effort.

    Regards,

    Max Verboncoeur

  • 0 in reply to Max Verboncoeur
    Prodigy 150 points

    Hi Max,

    is the alert signal SIL2 conform?

    Can the device monitor the capacity of an akku?

    BR

    martin

  • 0 in reply to Martin Sauer
    TI__Genius 17025 points

    Hello Martin,

    Section 7.3 ALERT Pin Operation in the BQ76905 Technical Reference Manual may help provide more information regarding what you're looking for.

    Our devices do not monitor the capacity of a battery. If you want to monitor information such as state-of-charge and state-of-health, a gauge may be better suited for your needs.

    Best Regards,
    Alexis

  • +1 in reply to Martin Sauer
    TI__Mastermind 24965 points

    Hi Martin,

    To build on Alexis' answer:

    We are working on a Q1 version of the BQ76907, which is the 7s version of the BQ76905 (same package/firmware). This will be SIL-1 and ASIL-A rated, which we have some customers using ASIL requirements decomposition to implement a system-level ASIL-B solution using two ASIL-A devices for redundancy.  You can consider this for your system.

    Integrated capacity calculations are a feature of gauges, which our part does not have. Our part does provide synchronized voltage and current measurements as well as Coulomb counting and charge integration, which are all of the tools necessary to implement your own gauging algorithm on an MCU.

    Regards,

    Max Verboncoeur