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BQ25122: Failure Modes of BQ25122

Lasse Korff
Prodigy 30 points
Part Number: BQ25122


Hi TI!

We are doing an analysis of our circuit which is including BQ25122.

Seen from the battery, then how can BQ25122 fail?

Do you have a failure mode overview similar to https://www.ti.com/lit/fs/sbva075/sbva075.pdf?ts=1661954706711 ?

I assume it could fail by going open or hard short to ground. Could it also fail by making a soft short to ground?

Regards,

Lasse

  • 0
    TI__Mastermind 18385 points

    Hi Lasse,

    To clarify, you would like to know the potential causes for failure of the IC or of charging? I will investigate if a similar document is available.

    In the events that you mentioned, the device has certain measures to protect the application system.

    -If VBAT is open then the device will oscillate between 'Charge Done' and 'Charge In Progress' as the BAT capacitor is charged and discharged.

    -If VBAT is shorted then a charging fault will be reported, charging will stop, and BAT_UVLO Fault will be reported. Lastly, a soft short to ground.

    -In the event of a soft short, the charger will only provide current up to the programmed max current. Additionally, the thermal monitoring can be incorporated to regulate charging in the event that the battery is heating up. Lastly a safety timer will prevent charging that goes on longer than a programmed time.

    Best Regards,

    Juan Ospina

  • 0
    Prodigy 30 points

    Hi Juan!

    Thank you for the explanation.

    What I am looking for is not how BQ25122 act if an external failure happens, but if BQ25122 itself fails, then what failure modes does it have?
    I am well aware that this happens very rarely, but if/when it does, then what can happen? So yes, a failure mode description similar to the document I linked to would be perfect.

    Is the design single point failure proof? Could the battery be shorted, open or softly shorted?

    I will mainly be interested in the parts of the IC facing towards the battery.

    Regards,

    Lasse 

  • 0 in reply to Lasse Korff
    TI__Mastermind 18385 points

    Hi Lasse,

    We don't presently have a document as the one you provided. I'm currently investigating the designers to provide a list of potential failures that you are looking for particularly relating to the battery. I will update you with further information when I've collected it.

    Best Regards,

    Juan Ospina

  • 0 in reply to Juan Ospina
    Prodigy 30 points

    Thank you Juan!

    Your help on this is much appreciated!
    Could you give an estimate of how long time will be needed to collect it? Are we talking days or weeks?

    Regards,

    Lasse

  • 0 in reply to Lasse Korff
    TI__Mastermind 18385 points

    Hi Lasse,

    I should be able to provide some better insight by Thursday this week.

    Best Regards,

    Juan Ospina

  • 0 in reply to Juan Ospina
    TI__Mastermind 18385 points

    HI Lasse,

    As an update I've been attempting to analyze what we can provide for you but unfortunately our teams FMA Champion is currently out of office until next Tuesday. I will do my best to provide a full analysis next week.

    Best Regards,

    Juan Ospina

  • 0 in reply to Juan Ospina
    Prodigy 30 points

    Thanks Juan!

    Next week will be fine!

    Regards,

    Lasse

  • 0 in reply to Lasse Korff
    TI__Mastermind 18385 points

    Hi Lasse,

    Thank you for your patience in this matter. As an update, I've been able to discuss with the Failure Mode champion this week. A Failure Mode Distribution analysis is typically reserved for our Functional Safety qualified parts as it requires a certain amount of designer resources. Because of this, this particular devices has not had an FMD analysis conducted yet. I've spoken to our design resources about when we may be able to conduct such an analysis but this may take a while longer, possibly in the order of weeks.

    I've sent you a friend request so we can continue this discussion via email.

    Best Regards,

    Juan Ospina