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Original question:

TPS23730: TPS23730 design_Transformer turn ratio check

TPS23731: TPS23731_Power loss_PM22806

Ching-Fei Ho
Prodigy 150 points
Part Number: TPS23731
Other Parts Discussed in Thread: PMP22806

Tool/software:

Hi, Diang,

Recently, I use PM22806 board with D100 non-installed, Q3, D18, D19, D17, R31 installed to do the test. However, I find that there is a big power loss at light load. I change the NMOS with smaller Ciss, Coss, there have about 0.8W improvement, but it still have about 2W power loss. Is there any other method to improve the power loss at light load? 

Thanks.

 

  • 0
    TI__Mastermind 37101 points

    Hi Ching-Fei,

    The light loss is too high, you may have a shoot through that increases the losses. I have one PMP22806 with below changes and could have an improved efficiency. Tested with 4-pairs input. Hope it can help.  

    R31 = 6Ohm

    D17 mounted

    Q3 = CSD19537Q3T

    D100 DNP

    Sync FET Snubber: 100Ohm (2512) + 0.47nF

    CP pin Snubber: 50Ohm + 0.47nF

    Half-FET bridge mounted 

    12V TPS23731 Test Report_Perliminay.pdf

    Best regards,

    Diang