Lenovo S145 -15iwl vcore inductor warm.. looking with oscilloscope there is a spike.

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  • Bartoloni
    Senior Member
    • Jul 2018
    • 140
    • Italy

    #1

    Lenovo S145 -15iwl vcore inductor warm.. looking with oscilloscope there is a spike.

    Hi, i have a Lenovo S145 that after 20 seconds shutdown and restart (it's working correctly on thse 20 seconds)
    everything seems ok, but on Vcore inductor ( this is an i3 with just 1 switching power supply for CPU)

    there is an output to teh CPU with a spike.. seems that inductor can't handle the input...
    replaced the capacitor (330) and the inductor (R15) without any change
    any idea? very thank you!

    input of the inductor seems as usual... only strange thing is that the upper/lower voltages seems to be 21V (main power line is 19.3) ... but not sure this can be a reading issue of the oscilloscope.
    Attached Files
  • Bartoloni
    Senior Member
    • Jul 2018
    • 140
    • Italy

    #2
    Wow..seems something new to the community... i see that 2 other time on other laptops, replaced mosfets, replaced capacitors... but still the spike, is something related to the driver? any idea?
    i can post more images about the signal before the inductor and also gates of the mosfets...

    if this can help.. the Vcore is starting at 1 volt and after a while descending to 0.7/0.8 like usual on these kind of CPUs... the accurate variation of the voltage seems confirm that the drivers is working correctly... but from where come from the small spike? a small timing issue on high side mosfet gate control?
    Last edited by Bartoloni; 12-13-2024, 12:33 PM.

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