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LM5069: About Gate current at Current Limit

Kaji@PAN
Mastermind 7775 points
Part Number: LM5069
Other Parts Discussed in Thread: CSD19536,

Hello,

I am considering the LM5069-1 device.
Regarding the figure below in the data sheet, how much Gate current flows at Current Limit?
This is the area indicated by the red circle.

Best regards,

  • 0
    TI__Guru** 105361 points

    Hi Kaji,

    Can we know why that parameter is of interest for you ?

    Best Regards

    Rakesh

  • 0 in reply to Rakesh
    Mastermind 7775 points

    Thank you for your reply.
    I would like to know the time from when an overcurrent occurs until ILIMIT is limited.
    The red circle in the diagram.
    This time must be affected by the Qg of the FET (CSD19536).
    Therefore, I assume that if I know the sink current of the LM5069 during ILIMT, I can calculate the time.
    Best regards,

  • 0 in reply to Kaji@PAN
    TI__Mastermind 38780 points

    Hi Kaji,

    Thanks for explaining the requirements. However, it's not possible to get the value of current. Because the GATE current is regulated in this region through a closed feedback loop to start limiting the current. This current is dynamically controlled based on the amount of overload beyond the current limit set point. Therefore, it's not possible to get any exact number. Hence, it's not mentioned in the datasheet as well. 

  • 0 in reply to Avishek Pal
    Mastermind 7775 points

    Thank you for your reply.
    I have two additional questions related to this.
    (Question 1)
    Which of the following timings does the TIMER pin capacitor charge?
    1.Timing when the overcurrent detection threshold is reached
    2.Timing of constant current control state
    (Question 2)
    The gate current changes dynamically when overcurrent is detected,
    for example, if a larger overcurrent flows, the time from when the current detection threshold is exceeded until the constant current control state is reached will be shorter?
    Best regards,

  • +1 in reply to Kaji@PAN
    TI__Mastermind 38780 points

    Answer-1: Timing when the overcurrent detection threshold is reached.

    Answer-2: I hope these two below waveforms answer your query.