+ Post New Thread
Results 1 to 3 of 3
  1. #1
    Member level 3
    Points: 1,204, Level: 7

    Join Date
    Jun 2013
    Posts
    64
    Helped
    3 / 3
    Points
    1,204
    Level
    7

    SMPS input capacitor calculation

    Hi All,

    In my Fly back smps circuit after the bridge rectifier there is a 22uF/400V capacitor. Instead of one 22uf/400V capacitor, what will happen If I use two number of 22uf/200V capacitor in series

    •   Alt11th January 2017, 14:40

      advertising

        
       

  2. #2
    Super Moderator
    Points: 15,558, Level: 30
    E-design's Avatar
    Join Date
    Jun 2002
    Posts
    1,963
    Helped
    487 / 487
    Points
    15,558
    Level
    30

    Re: SMPS input capacitor calculation

    You could do one of the last two options to get the same filtering effect as with one 400V 22 uF capacitor. In the last two options, the capacitor voltage rating is 200 V each.
    The resistors over the caps just balance the voltage equally over each capacitor. The 1 k resistor is the simulated load.



    •   Alt11th January 2017, 19:01

      advertising

        
       

  3. #3
    Super Moderator
    Points: 54,942, Level: 57
    Achievements:
    7 years registered
    Awards:
    Most Frequent Poster 3rd Helpful Member

    Join Date
    Apr 2014
    Posts
    11,126
    Helped
    2615 / 2615
    Points
    54,942
    Level
    57

    Re: SMPS input capacitor calculation

    Hi,

    Two 22uF capacitors in series will result in 11uF capacitance.

    You need four capacitors of 22uF/200V to get 22uF/400V. 2S2P

    This complies with stored energy: W = 0.5 × C × U × U
    Double the voltage and get four times the energy.

    Klaus



--[[ ]]--