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TPS61089: BOOST conversion efficiency

Kung Poyuan
Prodigy 241 points
Part Number: TPS61089

Tool/software:

HI 

The circuit is as attached. The input is 5V, and the output is 12V.

When the load at the 12V side is 0.3mA, the input current is 2.2mA, resulting in an efficiency of only 30%. How can this be optimized?

  • 0
    TI__Genius 16305 points

    Hi Kung,

    From our EVM, I have the same test for you.

    Vin=5.0096, Vout=12.15V, Iin=1.186mA and Iout=0.3mA;

    The efficiency is 0.613, which is much higher than 0.3.

    My switching frequency is about 3K and peak current is about 1A.

    Below are some possible reasons:

    1. The Current limit is too small that the peak current is limited, thus more switching pulse is needed, and the efficiency decreases.

    Please check the switching frequency to see if this is the reason.

    And you could change Rlim to have a try.

    2. the inductor has a large core loss or with high DCR that causes much loss in inductor.

    you could change the inductor with the EVM's to see if this is the reason.

    3. wrong value of the components

    4. input and output resistor decrease the efficiency (recommend to test eff without the two resistors)

    It is recommended to compare with EVM to see the differences.

    Best Regards,

    Fergus