This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

  • Resolved

LMR16030: Different type of 10 uH inductor cause thermal issue

Intellectual 930 points

Replies: 5

Views: 85

Part Number: LMR16030

Hi team,

My customer uses the LMR16030 as a 12V input, 3.9V/2.6A power supply.

Now he finds when using wound metal inductor(AMRU00060630100MA1) the IC and the inductor will both heat badly, but change to normal wire wound inductor(SLF12575) there will be no thermal issue. The inductor current is tested and they are basically the same. The test waveform is attached below, and the datasheet of both inductor are also attached.

Can you help me analyze the reason why the wound metal inductor can cause the IC thermal issue? The inductor value is the same to 10uH.

Thank you

Normal wire wound inductor current waveform(SLF12575), no thermal issue:

Wound metal inductor current waveform(AMRU00060630100MA1):

inductor_commercial_power_slf12575_en.pdf

chilixinAMRx_Series.pdf

  • Hi Taoran:

    from inductor datasheet , it looks both is fitting for 3A DC current and the current waveform looks normal. only metal inductor's inductance a little bit smaller than 10uH due to higher ripple current.

    So one assumption is the metal inductor core loss make the inductor hot, but it need confirm by inductor vendor. 

    Thanks

    Daniel Li

  • In reply to Daniel Li14:

    Hi Daniel,

    Thank you for your answer!

    Now my main question is why LMR16030 becomes heated while the inductor current waveform is similar.

    Can you help me analyze this abnormal scene and give me some possible answer? 

    Thank you again for your help.

    Gary Jiang

  • In reply to Taoran Jiang:

    Hi Gary:

    Can you help provide SW waveform of normal one and abnormal one in no load condtion? it will be helpful for us analysis the root cause, only desritpion of issue will be hard for us find the answer.

    Normally , in no load or light load conditon, it will be working at PFM mode so the frequency of SW wil be very low , the inductor curent is discontinue, so it should not be hot.

    Thanks

    Daniel Li

  • In reply to Daniel Li14:

    Hi Daniel,

    Thank you for your reply.

    Yes, in no load condition, it works in PFM mode and there is no thermal issue.

    Now my customer just provided SW waveform of normal one and abnormal one when outputting 3.9V/2.6A, and the waveform is attached below. Now he just send the board to me and I will test the waveform in no load condition, and I will post it later.

    For now, can you give me several assumptions? or do you need any other test waveform?

    The white waveform is the normal one and the yellow waveform is the abnormal one, it's basically the same.

  • In reply to Taoran Jiang:

    Hi Taoran:

    let's talk in the email for further discussion of this issue.

    Thanks

    Daniel Li

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.