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Why LT3471 efficiency in my project is 20%?

Hi  

LT3471 used to drive OLED, Output positive voltage 6.22V/78mA;Output negative voltage -4.58V/38mA,Input voltage 4.8V /681mA,that efficiency is only 20%,please check schematic ,what  is caused that ?attached schematic,thanks!PDF

Top Replies

    •  Analog Employees 
    Feb 5, 2021 +1 suggested

    Hi ,

    From a schematic perspective, it looks OK. I recommend using Schottky diodes instead of the diodes used.

    Things to check:

    1)  Ensure the inductors used are not saturating or have a high…

  • Hi ,

    From a schematic perspective, it looks OK. I recommend using Schottky diodes instead of the diodes used.

    Things to check:

    1)  Ensure the inductors used are not saturating or have a high ESR.

    2)  Ensure C6589 and C6596 are low ESR ceramics.

    3)  Ensure the diodes are working properly and not conducting in reverse or getting too hot.

    4)  Ensure the supply is stable by looking at the SW nodes. The pulse widths should not  vary with the same input voltage and output load.

    5)  Ensure input and output caps are low ESR ceramics.

    7)  Ensure the input voltage at Vin is not drooping and is staying at ~4.8V.

    8)  Ensure there is heatsinking for U6420 and it is not getting to hot.