help me finish simulating this circuit

Discussion in 'General Electronics Chat' started by high voltage123, Feb 25, 2012.

  1. high voltage123

    Thread Starter New Member

    Feb 23, 2012
    14
    0
    hii all
    i really hope find a solution to my problem here…i am designing a flyback converter (5 to 15 Vdc) i did all the design but i still didnt got the output—-i jss got 8V????
    so am lost dont knw wat to doo?? i attached my circuit with a waveform of the mosfit plz take a look…

    thnx in advance
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    With a standard 555 you do not need Q1 or Q2, the 555 already has similar output transistors, which can sink/source up to 200ma. Leave R4.

    Is the MOSFET a logic level unit? 5V is kind of low for this application.
     
  3. high voltage123

    Thread Starter New Member

    Feb 23, 2012
    14
    0
    so u suggest for me to change the input and try with anther 1 higher???? or to change the mosfit???
     
  4. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    Why 5V? 12V solves a lot of technical issues.

    If the MOSFET you have is not logic level this circuit will not work, it is that simple.

    If the voltage was 12V it will.

    And you can still eliminate Q2 and Q3 either way.

    If you changed out Q1 for a logic level MOSFET it might work, depending if the component was able to respond to 3.8V gate drive OK. Regular MOSFETs MUST have at least 10V drive on the gate.

    Bill's Index

    LEDs, 555s, Flashers, and Light Chasers

    Chapter 10 - Transistor Drivers

    Go down to the MOSFET section, it is the second half.
     
  5. high voltage123

    Thread Starter New Member

    Feb 23, 2012
    14
    0
    same problem again.. ichanged to 12V input in order to get 24V with changing the transformer primary and secoundery inductance but i only get 16V????/
     
  6. high voltage123

    Thread Starter New Member

    Feb 23, 2012
    14
    0
    is there anyway that can i upload my circuit here in order to check it?? i tried everything but still cant get the desired output
     
  7. crutschow

    Expert

    Mar 14, 2008
    13,003
    3,232
    You can attach the schematic file to your post using the Attachments (paper clip) icon in the "Go Advanced" window.
     
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