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Original question:

LM5118: Can LM5118 be used to achieve 2.5A max current for 5V output voltage

LM5118: Requirement for better recommendation for high efficiency at light load

Amelie Zheng
Genius 10865 points
Part Number: LM5118

Hi Team,

My customer now choose a buck-boost in DVR application, the requirement is 9-36Vin, 12Vout, 2A output current, low Iq, high efficiency at light load.

As first they would like to use LM5118. However, met problem.

When LM5118 operate in low power mode (output current is several mA), the efficiency is too low, which can't keep high efficiency at light load.

May I ask do we have much better recommendation about these requirement with high efficiency at light load?

  • 9-36Vin, 12Vout, 2A output current, low Iq, high efficiency at light load.
  • Customer said that they need to keep dozens mW at light load...(12Vout*3mA) 

Thanks!

  • 0
    TI__Mastermind 21720 points

    Hi Amelie,

    Thanks for reaching out with you questions and for considering the LM5118.

    Can you please let me know the efficiency requirement at light loads? Is there an input current consumption specification for when the load current is less than a certain value? This will help in selection the correct IC

    Please feel free to contact me directly.

    Thanks,

    Garrett

  • 0 in reply to Garrett Roecker
    TI__Genius 10865 points

    Hi Garret,

    Thanks for your reply.

    When using LM5118 at light load (several mA), the efficiency is about 40%. Customer needs about 60-70% when 9-36Vin to 12Vout at light load (several mA).

    I know that LM5150 improves efficiency at light load by alternating between low Iq stand-by and wakeup modes, even can realize 70-80%. However, it can only ouput 10.5Vout max...

    Do you have better recommendation?

    Thanks! 

  • 0 in reply to Garrett Roecker
    TI__Genius 10865 points

    Hi Garrett,

    Any update?

    Thanks!

  • 0 in reply to Amelie Zheng
    TI__Mastermind 21720 points

    Amelie,

    Does the application call for a buck-boost convert or just a pre-boost to keep the rail voltage above 12V? In the buck-boost portfolio there is currently not a low Iq buck-boost converter.

    Thanks,

    Garrett

  • 0 in reply to Garrett Roecker
    TI__Genius 10865 points

    Hi Garrett,

    Thanks for your reply.

    What customer need is buck-boost. what about solution high efficiency at load light?

    Thanks!