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Building lt spice transformer / help!

Discussion in 'General Electronics Chat' started by killivolt, Oct 6, 2013.

  1. ChrisP58

    ChrisP58 Well-Known Member

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    I think you're making it more complicated than you need to.

    For now, just take the Al (L is a subscript) value from the core datasheet, and multiply that by the square of the turns.

    Leave it to the core manufacturer to figure out what the Al is for any given core.
     
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  2. alec_t

    alec_t Well-Known Member Most Helpful Member

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    You really don't need inductance (or any other) values to 15 decimal places :).
    But Chris got the inductance as '~900uHy for each of your 4 windings', so put '900u' (or '0.9m') into Spice as the inductance values.
     
    Last edited: Oct 8, 2013
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  3. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

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  4. dave

    Dave New Member

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  5. killivolt

    killivolt Well-Known Member

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    Ok, I was using Mikes Calculator thinking I had one more step, I'll play around with it later.

    I've taken Rons, Suggestions and this is what I have now.
     

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  6. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

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    hi kv,
    The bottom of diode D4 is not connected.?, no path to the M2 source
    Eric
     
  7. alec_t

    alec_t Well-Known Member Most Helpful Member

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    Can't see an inductance value for HV-Primary?
     
  8. killivolt

    killivolt Well-Known Member

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    Eric, I tried to connect D4 I think I may need to spread thing out. M2's Path to source do you have a suggestion what to do?

    alec t, I was waiting to calculate that, it's a flyback from a TV, 6 turns 18g Mag wire. I don't know how to calculate it?
     
  9. alec_t

    alec_t Well-Known Member Most Helpful Member

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    Don't see how you can calculate it if the flyback core parameters are unknown. You could guestimate it by assuming the params are similar to your ferrite. If 14 turns gave you 900uH then 6 turns should give (6/14)^2 x 900 = 165uH by my reckoning.
     
  10. killivolt

    killivolt Well-Known Member

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    There both Iron just one of them is a powder and the other, well that's where I didn't know either. I'm ok, questimate.

    What does Eric mean by path?
     
  11. killivolt

    killivolt Well-Known Member

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    Never mind I figured it out.

    Thanks, I'll add the Inductance to HV Primary.

    I'm still not sure now who the center tap of the primary is to be done?
     
  12. killivolt

    killivolt Well-Known Member

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    Rev2......Edit: I forgot to add the Inductance of the HV Primary. Just fixed it.
     

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  13. killivolt

    killivolt Well-Known Member

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    I have the free version I can't run this Simulation on the Schematic in post #51, could someone check it out? Gotta go back to work now. Later.
     
  14. Inquisitive

    Inquisitive Super Moderator

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    LTSpice is 100% free.
     
  15. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

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    hi kv,
    A conductive path from the bottom of the D4 diode and the M2 FET Source pin.

    Without a conductive path from the bottom of the diode there will be no voltage between the Gate and Source of M2, the Gate is virtually 'floating'
    E
     
  16. killivolt

    killivolt Well-Known Member

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    Maybe I haven't set up the toolbar or something. Not sure what I'm done wrong?

    All I have is File, Edit, View, Window, Help.
     
  17. killivolt

    killivolt Well-Known Member

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    Thanks, I figured that one, when I re-read your post and path and source together. I have corrected it, but now I need all the tools in the toolbar? To Run it.

    It might be because I'm running it on a Mac.
     
    Last edited: Oct 8, 2013
  18. killivolt

    killivolt Well-Known Member

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    Hey Chris, I don't think I ever sent this to you.
     

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  19. killivolt

    killivolt Well-Known Member

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    I have a Windows version LT Spice using my VM Ware I have windows on one side of my Mac, I can share files as well.

    I have a toolbar now. I don't know how much trouble I will have but, I could run it. My Version of OS X is is 10.8.5 and I think the latest version of LT Spice is 10.7+, But,

    The windows version of LT Spice has the "latest" update. Not the Mac.

    I contacted them to let them know the trouble.

    kv
     
    Last edited: Oct 8, 2013
  20. killivolt

    killivolt Well-Known Member

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    I found I connected the left side of SG3525A wrong, I fixed them.

    Here is the new Drawing.
     

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  21. killivolt

    killivolt Well-Known Member

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    Here is the Original authors Schematic
     

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