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TLV704: Output Current Limit Transient Response Time

Carter Timm
Prodigy 210 points
Part Number: TLV704

Hello,

I'd like to place a crowbar circuit on the output of a TLV70433 regulator with 10µF of dedicated output capacitance and 2.2µF of dedicated input capacitance. The output will also have an additional 10µF of capacitance located six inches or so from the regulator and the input will have an additional 10uF within an inch that serves as an output filter component for a buck converter.

Can you elaborate on the output current limit transient response time of the TLV704? I see no mention of this in the datasheet and I'd like to make sure that the fuse in the crowbar circuit is able to reliably activate.

Thank you,

Carter

  • 0
    TI__Mastermind 23361 points

    Hi Carter, 

    When deciding on the crowbar, you need to ensure it can tolerate the in-rush current which is much higher than the current limit number of the LDO. The current limit may take hundreds of microseconds to be activated internally, and before this happen, the load current will be the in-rush plus any load current that may be exsited in the application.

    The in-rush is determined primarily by the output capacitance, is it possible to capture the in-rush with your baords? 

     

    Regards, 
    Jason Song

  • 0 in reply to Jason Song
    Prodigy 210 points

    Hi Jason,

    Thanks for the quick response. Yes, I will be able to measure inrush when this board revision is finished. Can you provide any min/typ/max spec on the current limit timing?

    Thank you,

    Carter

  • 0 in reply to Carter Timm
    TI__Mastermind 23361 points

    Hi Carter, 

    The current limit response time is not a test parameter and we know normally the time for the LDO's current loop to fully engage is in the range of hundreds of microseconds. 

    Regards,
    Jason Song