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LM5176-Q1: Fault (Hiccup mode /Current limit) Quesiton.

Part Number: LM5176-Q1
Other Parts Discussed in Thread: LM5176

Hi, Ti teams

Currently we are using the LM5176-Q1.

In order to protect the FET and inductor used in the LM5176, a cycle-by-cycle current limit is added and used.

Here, I am trying to enable Hiccup mode together, but I am curious how the MCU can find out whether the IC is stuck at the current limit or entering the Hiccup mode.

In other words, which pin of the IC should be monitored and compared by the MCU, I wonder if the MCU can know the fault (Hiccup mode, current limit) status of the IC.

Best regard

Thank ou

  • Hi Minho,

    Thank you for using the LM5176. When the circuit enters hiccup mode, you can see the following:

    • SS is discharged, and it will restart after about 4000 cycles.
    • COMP stays high
    • VOUT is reduced
    • VCC maintains

    Hope this helps.


    Youhao Xi, Applications Engineering

  • Hi, Youhao

    Even if we continue to give high signal to EN pin to LM5176, please check if we can see that the mentioned contents (SS, COMP, VOUT, VCC) change

    when entering Hiccup mode.

    Best regard

    Thank you

  • In addition, please review whether PGOOD is changed to low in hiccup mode.

  • HI Kim,

    the behavior of the signals above will only behave as explained when EN is high.

    Otherwise the internal Logic in the LM5176 will shut down and e.g. VCC will be switched off.

    PGOOD: as you can see in the datasheet PGOOD is related to the level of the FB pin. So if the load would still be on the output the VOUT and also the FB will go down, which will also make PGOOD going low.

    But just in case the load on the output would recognize a voltage drop and switch off before the PGOOD triggering level is reached. It could be the case that PGOOD would stay high. So this depends a some more conditions, so general statement can not be made.

    Best regards,


  • Hi, Stefan

    youaho says that VCC is maintained, you say that VCC is off, and I think it is right that VCC is off,

    Please confirm what VCC means to maintain.

    In addition, I do not understand the meaning of switch off in the sentence below in PGODD, so please explain further.

    (But just in case the load on the output would recognize a voltage drop and switch off before the PGOOD triggering level is reached.)

    Best regard

    Thank you

  • Hi Minho,

    let me clarify my statement above:

    Vcc will switch off if Enable is low. If Enable is high Vcc stays on even in Hickup mode.

    So Youhao's statement is correct.

    Regarding the second question:

    This meant for the load on the Converter. If the load would be removed (switched off) by some other mechanism.

    Best regards,


  • Hi Minho,

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