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TPS61378-Q1: TPS613783 inductor temperature to high even without load

F_F_S
Prodigy 150 points
Part Number: TPS61378-Q1

Tool/software:

In my application the inductor temperature is about 30°C over the ambient temperature also without load..

Can you help me?

  • 0
    TI__Mastermind 18510 points

    Hello,

    Is the 12V Vout stable?

    What's the surface temperature of the TPS613783-Q1?

    If the 0.1A Iout was loaded, will the inductor temperature be much higher? 

    Could you measure the SW voltage with high bandwidth and also send me the layout?

    Thank you.

    Regards

    Lei  

  • 0 in reply to Lei Zhong
    Prodigy 150 points

    Hi,

    yes the 12Vout is stable.

    I think that the problem is the hight inductor ripple current at low Iout current with 1,5uH of inductor.

    With this high ripple the ac lose it's very high.

    In the TPS613783 datasheet it is recommended to make the peak-to-peak current ripple between 800 mA to 2 A when selecting the inductor. This can be a problem if I like for example use a 10uH to recude the IL ripple and the AC lose.

    Normaly the system work with Iout 30mA; with 30mA the ILripple is about 428% .

    Can you help me to recalculate the right value or I need to change the P/N of boost converter?

  • 0 in reply to F_F_S
    TI__Mastermind 18510 points

    Hello,

    When 1.5μH inductor is used, the inductor current ripple is in the reasonable range and there won't be a large AC loss and make the inductor inductor temperature so high.

    When the average inductor current (input current) is very small, for example, tens of mA, the ILripple% is always very high and will be ignored.

    Regards

    Lei