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Need details about gate drive pulse transformer

Discussion in 'High Voltage' started by samuel.sam77, Mar 29, 2012.

  1. samuel.sam77

    samuel.sam77 Member

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  2. johansen

    johansen Member

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    there's nothing special about gate transformers other than the fact that you need to construct them for a very low leakage inductance.
    this means you may need to have multiple layers of windings rather than just winding the primary first and the secondaries over the top.

    the number of turns will be the same as any other transformer assuming you need a fixed 50% duty cycle.
    if not you will have to increase the number of turns as appropriate accounting for the highest volt seconds that will ever be applied to the core.

    and lastly, that 56 ohm gate resistor is the last thing you need to optimize.
     
  3. samuel.sam77

    samuel.sam77 Member

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    Thanks Mr johansen for quick reply ..will u specify the examble number of turns pri and sec for 1:1:1 transformer
     
  4. dave

    Dave New Member

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  5. johansen

    johansen Member

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    sounds like homework

    the formulas are on wikipedia.
    since you are using square waves, use 4.0 instead of 4.44
     
  6. samuel.sam77

    samuel.sam77 Member

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    dear johan i designed pulse transformer using EE25/6 pri-80 turns and sec 60,60 turns ..my pulse generating ic getting too hot

    also give me the formula with an examble

    or give me the details to design my requirement

    1:1:1 half bridge mode ,Mosfet irf840 or irfp250 ,output current 500mA...frequency 60KhZ to 5Khz
     
  7. johansen

    johansen Member

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    you haven't provided enough information

    If you want a pulse transformer that can be directly driven from a Ka3525 that may turn out to be a difficult task if you want to go as low as 5Khz.
    You may have to use an expensive amorphous metal core, rather than a standard ferrite transformer to do that.
    most people just use an amplifier, two transistors, or two mosfets to drive the pulse transformer.

    also, did you put a capacitor in series with the primary winding? if not then the transformer probably got saturated.

    when calculating the number of turns you must use the lowest frequency.

    on the surface it sounds like you have enough turns.
    what is the core area of your transformer, flux density, permeability, air gap, ?
     
    Last edited: Mar 30, 2012
  8. samuel.sam77

    samuel.sam77 Member

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    dear johanson sorry for late reply i have designed pulse transformer its working fine with Ka3525 ,the out of pulse 24V pk -Pk is getting.
    now i want to change the ka3525 to Pic micro controller 16f690 how to connect these out put signal to pulse transformer like same as Ka3525 ..plz help me here i added the driver circuit. just need p1A and P1b(out a,out b) how to connect these to transistor.
     
    Last edited: Apr 8, 2012

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