Flyback dc to dc converter switching frequency

Discussion in 'The Projects Forum' started by JMS026, Oct 1, 2015.

  1. JMS026

    Thread Starter New Member

    Oct 1, 2015
    2
    0
    Hello friends, I am working on a project where I used flyback dc to dc converter to power up all circuit components.
    My issue is related to switching frequency. When I use 100KHz switching frequency(using TOP Switch) my circuit works properly but when I switch to 400KHz (using DPA switch) the issue of noise interference in secondary side is started.

    Is there any trend to use special filter capacitor/inductor at special locations to avoid primary sided noise from coupling with secondary sided circuit?
     
  2. crutschow

    Expert

    Mar 14, 2008
    12,988
    3,226
    Hard to advise you without a schematic of your circuit.
     
  3. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,969
    744
    Sounds like harmonic distortion, lets have a circuit diagram please...
     
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  4. Roderick Young

    Member

    Feb 22, 2015
    408
    168
    Do you have a schematic? Is there a snubber on your switch?
     
  5. DickCappels

    Moderator

    Aug 21, 2008
    2,647
    632
    Yes, there are three-legged filters to clean up very high frequency noise.

    Yes, your schematic is important.

    Do you know how the noise gets from the power supply primary to the circuit that is experiencing the interference? There are many possible paths besides through the rectifier on the transformer's output and the higher the frequency the more significant these sneak paths become (magnetic induction of the signal into the chassis, capacitive coupling of high dv/dt electric fields, ground loops, etc.
     
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  6. JMS026

    Thread Starter New Member

    Oct 1, 2015
    2
    0
    Thank you all of you for your interest. I'm attaching schematic diagram for reference.
     
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