Swithching regulator (Buck Converter) with LTSpice question

Discussion in 'General Electronics Chat' started by RobinLeblond, Oct 20, 2018.

  1. RobinLeblond

    Thread Starter New Member

    Oct 20, 2018
    2
    0
    Hello, I'm in the process of learning switching regulator and I'm using LTSpice as a simulator and teaching help. I found a video on Youtube explaining the SR, and I did exactly what it was demoed and didn't get the same results.

    Simply said, I getting the same result but with a 300mV at the output instead of 5.6V, why ?

    Here is the link of the video :

    In attachment, you will find my LTSpice schema and a few screenshots.

    Thanks a lot!

    Thanks
     
  2. ericgibbs

    Moderator

    Jan 29, 2010
    8,546
    1,722
    hi Robin,
    Welcome to AAC.
    Will run your LTS sim, let you know how it goes.
    E

    EDIT:
    Did you try to post link to the online video.???
     
    Last edited: Oct 20, 2018
  3. Bordodynov

    Well-Known Member

    May 20, 2015
    2,344
    727
    Hi. Vout<Vcc*D
    ==> .param D=0.5 Vout=5.6V
     
  4. crutschow

    Expert

    Mar 14, 2008
    23,099
    6,850
    Because the switching duty-cycle in your simulation is 5% instead of 50%.
    A 5% duty-cycle gives a theoretical output of 600mV (with an ideal diode).
    See below with 50%.
    Edit: Bordodynov beat me to it.

    upload_2018-10-20_8-26-55.png
     
  5. RobinLeblond

    Thread Starter New Member

    Oct 20, 2018
    2
    0
    Crap!!! Thanks you all ! Everything is in the details !!! Thanks!
     
  6. crutschow

    Expert

    Mar 14, 2008
    23,099
    6,850
    Especially in electronics. :rolleyes:
     
    cmartinez likes this.
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