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BQ24610: issues

Ivy Jin
Expert 4475 points
Part Number: BQ24610
Other Parts Discussed in Thread: BQ24725

Hi team,

My customer use BQ24610 in their new project, but they meet below issues now, could you please help give some comments?

Thank you!

BQ24610 is used to charge 5S battery packs, and the charging input voltage is 24V±0.7V.

1. The customer can hear a slight fire noise from the connector while the battery is plugged in; the problem persists when the customer tries again with the EVM board; (This issue is not found in the customer's other 4S solution which use BQ24725)

2. Customer sets trickle current 300mA and constant current 2A charging; Actual tests found that the battery goes directly into constant current charging, with no obvious trickle charging process.

3. During the test, repeatedly plug and unplug the charging input and the charging IC is burned (the chip emits smoke)

Regards,

Ivy

  • 0
    TI__Mastermind 40305 points

    Dear Ivy,

    I will address the questions in order:

    1. Please describe exactly what test conditions this occurs at (ie battery voltage, system current, charge current etc.) What is connected to the solution/EVM?

    2. What battery voltage is applied when this happens? If the VFB pin is above 1.55 V typical when plugged in the battery will start charging in fast charge instead of pre-charge.

    3. Do you have an input hot plug filter? If not I would recommend adding one as detailed in "Section 10.2.1.2.5 Input Filter Design."

    Thanks,

    Mike Emanuel

    Please click "Resolved" if this answered your question.

  • 0 in reply to Michael Emanuel35
    TI__Expert 4475 points

    Hi Mike，

    Thank for your comments.

    1. Please describe exactly what test conditions this occurs at (ie battery voltage, system current, charge current etc.) What is connected to the solution/EVM?

    Feedback: The customer has tested the battery voltage at 18V-20V and found that the behavior is the same, with a slight fire sound when the battery pack is inserted in J5; (at this point, there is no AC power connected, i.e. J1 is disconnected)

    2. What battery voltage is applied when this happens? If the VFB pin is above 1.55 V typical when plugged in the battery will start charging in fast charge instead of pre-charge.

    Feedback: The battery voltage is 16.7V, which is a total of 5S; May I ask that whether the voltage limit for the fast charge can be set?

    3. Do you have an input hot plug filter? If not I would recommend adding one as detailed in "Section 10.2.1.2.5 Input Filter Design."

    Feedback: Yes. The RC circuit is placed on the AC output (in front of the anti-tamper PMOS), I will send you the total schematic through e-mail.( In this time, the J5 is connect to the battery pack, the ground of J1 is connected to the GND of the power supply, and the ACPOWER is plugged repeatedly)

    Thanks again for your comments!

    Regards,

    Ivy

  • 0 in reply to Ivy Jin
    TI__Mastermind 40305 points

    Dear Ivy,

    1. What is connected to your SYS pin when this happens? Can you describe what else is connected to the EVM? Does the noise persist, or is it just a one time thing? If it is a one time thing, it may be related to the inrush of the output capacitance. See the below reference material.

    2. Yes, the charge voltage limit can be set on the EVM by changing R25 and R28.

    3. If the input hot plug filter does not work, you need to find another way to mitigate inrush current. Please see the following white paper and application report.

    https://www.ti.com/lit/eb/slyy168/slyy168.pdf

    https://www.ti.com/lit/an/slva670a/slva670a.pdf

    Thanks,

    Mike Emanuel

    Please click "Resolved" if this answered your question.

  • 0 in reply to Michael Emanuel35
    TI__Expert 4475 points

    Hi Mike,

    The SYS pin is be floated, the EVM is only been connect to the 18-20V battery pack. The noise is a one time thing.

    I will let the customer to add the output capacitance firstly to see if the issue can be resolved.

    Thanks!

    Regards，

    Ivy

  • 0 in reply to Ivy Jin
    TI__Mastermind 40305 points

    Dear Ivy,

    I think there was a misunderstanding. In SLVA670A it says, "Increasing the system capacitance to reduce transient voltage dips comes at the cost of increased inrush current generated from charging the increased capacitance." I recommend finding a way to mitigate the inrush current by the solutions shown in the two reference materials given.

    Also, I do not hear a noise with a 23.6 V VCC and hot plugging a 19.7 V battery emulator on my BQ24610 EVM.

    Thanks,

    Mike Emanuel

    Please click "Resolved" if this answered your question.