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LM5026: LM5026_efficiency

user4719845
Intellectual 315 points
Part Number: LM5026

Hi

I has a design use LM5026 Vin input cap is 0.1uF, but low load efficiency is no good does any calculation method or recommend.

  • 0
    TI__Mastermind 31580 points
    Hi,

    Can you post the efficiency measurements from the power stage and the specification that the design must meet.

    Thanks

    Peter
  • 0 in reply to Peter Meaney
    Intellectual 315 points

    I use LM5026 design a fly-back Vin=12V Vout=5V/8A, but low load has 80mA, efficiency is 87%

    I want Improve efficiency 90%, my Clamp capacitor is 0.1uF .

  • 0 in reply to user4719845
    TI__Mastermind 31580 points
    Hi

    At 80mA load at 12V the load power is 960mW. If the efficiency is 87% then the power dissipated is 143mW. to reach a target of 90% the power dissipation need to drop to 106mW, lets say 100mW. So we need to save 43mW or 30% of the power dissipation figure.

    I assume you are using an SR driver on the output, which T part number is it , and is it going into a low power mode ?

    Please check your design to reduce any static losses across Vin and Vout due to resistive dividers and bias currents for control circuits. Minimising these currents will help.

    87% efficiency at 1% load is already a very good efficiency figure!

    Regards

    Peter