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LM5118: LM5118 Inductor Loss

Kuan Wei Chen (Kevin Chen)
Genius 9710 points
Part Number: LM5118

Dear Team,

My customer is using LM5118 for:

Vin:40-60V

Vo:54V

Io:1.5A

They test the circuit and find out inductor is too hot(more than 75dC)

Do you have any suggestions?

PM2120_series.pdf

BR

Kevin

  • 0
    TI__Mastermind 46905 points
    Hi Kevin,

    the material of the inductor core is iron, which may not fit the high frequency application. please check with the inductor vendor the acceptable frequency, and also the switching frequency of the LM5118
  • 0 in reply to Jasper Li
    TI__Genius 9710 points
    Dear Jasper,

    Thanks for the suggestion.
    If the customer Vo can be 51~54, can LM5118 only operate under 51V?
    If Vo higher 51V, only pass through and no switching.

    BR
    Kevin
  • 0 in reply to Kuan Wei Chen (Kevin Chen)
    TI__Genius 9710 points

    Dear Jasper,

    The customer already builds an evaluation board by themselves, so your comments are quite important to them at this time frame.

    They tested the efficiency, but not sure the reason why 40V have lower efficiency compared to the result from the Webench which have the highest efficiency during 40V.

    My comments are 40V have the higher current which will cause the higher conduction loss, so the reason they have such low efficiency might be they choose a high Rdson MOS.

    Do you have any comments to improve efficiency?

    BTW, do you have any suggestion to reduce LM5118 itself loss even only reduce 0.3W?

    11263.pdf

  • 0 in reply to Kuan Wei Chen (Kevin Chen)
    TI__Guru* 76815 points
    Hi Kuan Wei,

    Efficiency can be affected by many factors, including the layout and component selections. You may slow down the switching frequency a little, to save 0.3W losses.

    Thanks,
    Youhao Xi