Zero current switch resonant buck converter

Discussion in 'Homework Help' started by Ahmad Itani, May 8, 2016.

  1. Ahmad Itani

    Thread Starter New Member

    Apr 11, 2016
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    0
    I'm designing a full wave ZCS buck converter with input 12V and output 5V with Pout=2W.
    My question how can the switching frequency (20kHz, 60kHz, ...)affect the output average voltage and affect the shape of the waveform? thank you
     
  2. DickCappels

    Moderator

    Aug 21, 2008
    2,647
    631
    Your question is fairly open-ended. Generally speaking, designing for a higher frequency puts more dependence on the speed of the active components and parasitic reactances.
     
  3. Ahmad Itani

    Thread Starter New Member

    Apr 11, 2016
    10
    0
    I've attached my project questions and my circuit on psim. circuit.png
     
  4. MrAl

    Well-Known Member

    Jun 17, 2014
    2,418
    488
    Hi,

    Theoretically the frequency doesnt affect the average the duty cycle does, but when the cycle time is comparable to the turn on or turn off time of the switching device then it can but only if it's in a feed forward type converter. With the right feedback though it's a different story, the duty cycle would be changed to compensate if needed by the error amplifier and associated circuitry.

    The shape of the waveform may change a little because of the LC natural resonance, but again with the right feedback a slightly curved output vs a straight line up and down would stll be compensated for.

    I would think you'd be more concerned with getting the zero current or voltage timing right, unless you got that already. There is a general form for the average though and that is the mean:
    (1/T)*integral f(t) dt
    over at least one period T.
    f(t) is determined from the circuit arrangement.

    I dont have that much experience with resonant buck converters but we can look around on the web for more information too.
     
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