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BQ24133: How to confirm the operation of overcurrent protection

Shinichi Inoue
Guru 21701 points
Part Number: BQ24133

Tool/software:

Dear Specialists,

My customer is considering BQ24133 and has a question.

I would be grateful if you could advise.

---

I'd like to check the operation of the overcurrent protection on the battery charging side described in 9.3.13 of the BQ24133 datasheet.

Could you please let us know how to confirm.

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I appreciate your great help in advance.

Best regards,

Shinichi

  • 0
    TI__Guru**** 166876 points

    HI Shinichi,

    I am researching this.  This spec item is tested on the tester but the tester puts the IC into a test mode that I cannot share. I will reply by mid week.

    Regards,

    Jeff

  • +1 in reply to Jeff F
    TI__Guru**** 166876 points

    Hi Shinichi,

    I checked with our product test team and they place the charger into test mode and test a scaled down version of the current.  So the customer cannot do that.  On other devices, I have tested similar OCP specs by doing the following on an EVM:

    1. short the current sense resistor between SRN and SRP - this turns the charger into a buck converter that regulates output voltage

    2. use an electronic load or even tapping a power resistor between GND and output voltage to apply a fast rising load transient  >= IOCP_HSFET=6A.  Note that the leads between the load and EVM board need to be very short and twisted to minimize inductance or the rise time might too slow

    3. monitor the PH node and inductor current to see the HS FET on time- the OCP should turn off the FET before the duty cycle = VOUT/VIN * fsw predicts

    If the inductor has ISAT << 6A, the inductor will saturate, causing the inductor current to spike and OCP to trip.

    Regards,

    Jeff

  • 0 in reply to Jeff F
    Guru 21701 points

    Hi Jeff,

    Thank you for your reply.

    Let me confirm.

    Do you mention the methods you presented (1. to 4.) be applied to BQ24133?

    If so, I will share with the customer.

    I appreciate your great help and cooperation.

    Best regards,

    Shinichi

  • +1 in reply to Shinichi Inoue
    TI__Guru**** 166876 points

    Hi Shinichi,

    Yes.

    Regards,

    Jeff

  • 0 in reply to Jeff F
    Guru 21701 points

    Hi Jeff,

    Thank you for your reply.

    I'll share your suggestion with the customer.

    When the customer has an additional question, I consult you again.

    I appreciate your great help and cooperation.

    Best regards,

    Shinichi