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TPS61088EVM-677: Low Efficiency from 3.3 to 12V at 8W Load

VIVEKANANDHAN RAJENDRAN
Prodigy 40 points
Part Number: TPS61088EVM-677

Tool/software:

We conducted the EVM test for 3.3V to 12V output at 8W load and noticed that the efficiency is not within the desired range, at only 72% when the same inductor (1.2uH) used in the EVM board.
We tried replacing it with a 2.2uH inductor, but only achieved 74% efficiency.

Please see the test results below.
Inductor L1     Vin      Iin       Vout           Iout           Efficiency
1.2uH             3.3      3.47    12.13       0.6739              72%
2.2uH             3.3      3.35    12.13       0.674                74%

Could you please suggest a method to improve the efficiency for 8W, 3.3V to 12V output?

  • 0
    TI__Genius 16325 points

    Hi Vivekanandhan,

    thank you for reaching out.

    From the datasheet figure 6-2 and 6-4, we can see the efficiency is about 90% when Vin=3.6V and Vout=12V.

    The unwanted low efficiency could be resulted from below reasons:

    1. When customer use long and thin wires at input side, there will be high voltage drop on the wires.

    If they just read the voltage on the source, this could cause wrong result with the efficiency calculation.

    It is recommended to read the true input voltage with the VIN & GND connector on EVM

    2. Please check the parameters different from original EVM.

    These could cause much different on efficiency.

    Please send the schematic for us to check.

    Best Regards,

    Fergus