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LM5155: Any protection functions that can be stopped by a latch on LM5155

Conor
Guru 12050 points
Part Number: LM5155

Hi, 

The LM5155 has the following protection features

-----
Protection features
- Constant peak current limiting over input voltage
- Optional hiccup mode short-circuit protection
- Programmable line UVLO
- OVP protection
- Thermal shutdown
-----

Are there any other protection functions not listed in the data sheet? I would like to know if there are any protection functions that can be stopped by a latch.

Thanks,

Conor

  • 0
    TI__Genius 10385 points

    Hi Conor,

    Thank you for using E2E forums, what do you mean by stopped by a latch? the OVP protection is for the output voltage sensed at the FB pin, and when the voltage there goes above the OVthreshold voltage the switching stops as the OVP is triggered.

    BR,

    Haroon

  • 0 in reply to Haroon Wardak
    Guru 12050 points

    Hi Haroon,

    Sorry, I will clarify the question.

    Conor said:
    Protection features
    - Constant peak current limiting over input voltage
    - Optional hiccup mode short-circuit protection
    - Programmable line UVLO
    - OVP protection
    - Thermal shutdown


    Q1.
    Are there any other protection functions available for the LM5155 other than those listed above?

    Q2.
    I am concerned about whether the device latches when the protection function is activated. Checking the datasheet and your comments, it appears that the 'OVP Protection' performs a latching operation. If you know of any other protection functions that do latch act, please let us know.

    Thanks,

    Conor

  • 0 in reply to Conor
    TI__Genius 10385 points

    Hi Conor,

    1. I think that should be all the protection functions for LM5155.

    2. Yes the OVP protection will latch as soon over voltage is triggered, so it is not doing the hiccup mode protection which is also listed there but that is mainly for LM51551 device as it is disabled for Lm5155. In hiccup protection mode where instead of latching the output it the switching will pause for some cycles and then will resume detecting for over current. Other than that there is the cycle by cycle current limit as well that turns off FETs when current limit is violated.

    BR,

    Haroon

  • 0 in reply to Haroon Wardak
    Guru 12050 points

    Hi Haroon,

    Thank you. Current limiting is implemented on a cycle-by-cycle basis, so it is not a latching operation. Also, OVP also returns to running mode once the OVP region is exited, correct? I am concerned whether there are any protection functions that require external control for the return, such as turning off the enable and restarting, etc., in the method of return.

    Thanks,

    Conor

  • 0 in reply to Conor
    TI__Genius 10385 points

    Hi Conor,

    Yes current limiting is cycle by cycle, you are right. Yes it will return back to running mode once OVP is exited by Vout getting lower and FB gets below the OVP threshold. 

    Hope this helps.

    BR,

    Haroon

  • 0 in reply to Haroon Wardak
    TI__Genius 10385 points

    Hi Conor,

    I will close this thread. If you have further questions just reply on this thread.

    BR,

    Haroon