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LM5022: Does LM5022 has OCP and skip or hiccup mode？

Marc Liu
Expert 3610 points
Part Number: LM5022

Hi Team,

Does LM5022 have OCP? How about the stability under very light load, does it have skip or hiccup mode？

Thank you!

Marc

  • 0
    TI__Mastermind 21720 points

    Hi Marc,

    Thanks for reaching out with your question.

    The LM5022 has cycle by cycle switch peak current limiting. When the peak current limit voltage is exceeded the gate drive pulse is terminated until the next clock cycle. This is pretty standard peak current limiting.

    There is no hiccup mode functionality in the LM5022.

    Please let me know if you have any questions.

    Thanks,

    Garrett

  • 0 in reply to Garrett Roecker
    TI__Expert 3610 points

    Hi Garrett,

    Thanks for your reply.

    I have one more question about stability of LM5022 under very low loading. From figure 1 of datasheet, the wave only shows down to 50mA.

    Should I set R0 = +∞ in Chapter 8.2.2.10 to calculate the compensation?

    Thank you!

    Marc

  • 0 in reply to Garrett Roecker
    TI__Expert 3610 points

    Hi Garrett,

    Can over current limit be used as short protection? I think they has something similar but can't be treated as the same thing, right?

    Thank you!

    Marc

  • 0 in reply to Marc Liu
    TI__Mastermind 21720 points

    Marc,

    Figure is just showing the efficiency down to ~50mA, as the load decreased the efficiency will get worse.This doesn't mean that the loop is unstable.

    The compensation should be calculated for the worst case operating condition. For a boost regulator this is when the input voltage is at the minimum value and the output load current is at the maximum value. This will ensure that the loop is stable at other loading conditions.

    In a boost converter OCP doesn't provide short circuit protection as the diode in the power train will conduction when VIN is less than VOUT. So if the output is shorted the input supply is shorted as well.

    Please let me know if you have any questions.

    -Garrett