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LM1117: current limit response and the delay time

user4979989
Intellectual 2800 points
Part Number: LM1117

Hi team,

The typical current limit of LM1117 is 1.2A.

I would like to know what is the response after LM1117 detects current limit, shutdown the output and latch?

What is the delay time(response time) between LM1117 detects current limit to react the protection?

Thank you.

Regards,

Allen

  • 0
    TI__Guru 50090 points

    Hi Allen,

    The current limit response of a linear regulator is a secondary control loop. The primary goal is to properly regulate voltage. Which means there is a delay in the current limit response. 

    When any linear regulator gets into current limit, the voltage across the regulator increases as VOUT drops and the power dissipated increases (VI). This results in thermal shutdown. As the device cools, it will restart and if whatever caused the device to enter current limit is still present the cycle will repeat. 

    We made the TLV767 as a much better than replacement to a 1117. This has superior inrush control, fold-back current limit, and if needed we have a back door to make it latch-off in the event thermal shutdown occurs. (This would be cleared by cycling enable or VIN).

    I hope this helps to answer your question.