Series resonant converter- basic question

Discussion in 'General Electronics Chat' started by Evanor, Jan 14, 2015.

  1. Evanor

    Thread Starter New Member

    Apr 24, 2014

    I am studying some about series resonant converter but stuck to understand one thing from DC gain-frequency graph.

    The circuit:
    DC gain to frequency plot:


    They say:
    "As the load decreases, the Q decreases and the result is that the frequency needs to increase significantly to keep the output regulated."

    I have problem to understand this.
    Assuming that my converter have LEDs as a load looking on equation Q=Z/R if the load decreases the Q increases and then I have to do nothing with frequency because if number of LEDs is lower so DC gain can also be lower.
    Is that right? Thanks in advance.
    Last edited: Jan 14, 2015
  2. nigelwright7557

    Distinguished Member

    May 10, 2008
    A LLC converter has a higher frequency for a light load and a lower frequency for a higher load.
    At least that's how mine work ! lol
    As the load increases the frequency will decrease to counteract the demand.