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Original question:

BQ24618: BQ24618 failing over and over...

BQ24618: IC Blowing up as soon as battery connected

joelsa
Prodigy 30 points
Part Number: BQ24618

Hello everyone and good afternoon,

I am using the BQ24618 in one of my designs to charge a 6-cell Li-Ion Battery, but I am experiencing some problems with it. 

The input/system side of the design seems to work fine. When I connect power, the PG indicator LED is turned on, so ~PG is low, indicating good power supply. I can also power the system via the two high-side back-to-back However as soon as I connect the battery, the IC itself releases smoke and gets destroyed immediately, even with no power supply or no system load connected. This is the second board where this happens and I have carefully checked all of the connections for shorts or open circuits, so I can rule out a soldering error and am confident the PCB is manufactured correctly according to the schematic.

I have attached an image of the schematic.

Is there any obvious mismatch with the datasheet that I overlooked? Does anybody have a clue where this error might originate?

Thank you very much and best regards,
Joel

Schematic

  • 0
    TI__Mastermind 40375 points

    Dear Joel,

    We require a 1 uF REGN capacitor. Please replace this capacitor and let me know if you see any difference.

    Is the battery the correct polarity when plugged in?

    Thanks,

    Mike Emanuel

    Please click "Resolved" if this answered your question.

  • 0 in reply to Michael Emanuel35
    Prodigy 30 points

    Hi Mike,

    thanks for the swift reply.

    Thanks for the hint, I will certainly try that, but I am not very hopeful that it resolves the issue completely. The output capacitance of the Linear Regulator should not make such a night and day difference that the IC gets destroyed.

    I am thinking it's more of a transient issue, but then again a 3µ3 inductor does not store too much energy either.

    When I am trying it the next time, which pins should I measure on the scope? I am thinking of: PH, SRP, SRN and ACN, in order to get some understanding of what's going on.

    Best regards

    Joel

  • 0 in reply to joelsa
    TI__Mastermind 40375 points

    Dear Joel,

    Can you capture SRP, VCC, PH, and the current from the battery?

    Have you verified the polarity of the battery upon plug in?

    Thanks,

    Mike Emanuel