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high voltage half bridge mode

Discussion in 'High Voltage' started by samuel.sam77, Mar 28, 2012.

  1. samuel.sam77

    samuel.sam77 Member

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    My mos fet keep blown
     
  2. Sceadwian

    Sceadwian Banned

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    What Mosfet?
     
  3. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    It blew up thats why you can't see it any more. :p
     
  4. dave

    Dave New Member

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  5. Reloadron

    Reloadron Well-Known Member Most Helpful Member

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    I see Q1 & Q2. I see Earth Grounds, Chassis Commons and Signal Commons all over the place? Q2 gate goes to what looks like Earth Ground through 10K resistor, Q1 gate goes to Chassis Common through a 10K resistor? I may be missing something but I don't get it? Maybe someone else understands it.

    Ron
     
  6. ronsimpson

    ronsimpson Well-Known Member Most Helpful Member

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    Please send information on your gate drive. CON1.

    Not that it matters much but; LD2 will breakdown at -5 volts and you have it connected to the power line. At 2mA it will not over heat. Just saying it is rated for no more than -5 volts.
     
  7. ronsimpson

    ronsimpson Well-Known Member Most Helpful Member

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    Now I see your gate drive!
    What is JP1 14 pin IC?
     
  8. ronsimpson

    ronsimpson Well-Known Member Most Helpful Member

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    I think you are killing the gate on Q1.
    A dead Q1 might over current Q2.
     
  9. samuel.sam77

    samuel.sam77 Member

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    thanks for reply ,irf840 n-channel mosfet in half bridge mode ,i replaced microcontroller instead of sg3535..but output pulse are quit good but when connect mosfet and transformer suddenly blown what is the problem inmy circuit
     
  10. samuel.sam77

    samuel.sam77 Member

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  11. samuel.sam77

    samuel.sam77 Member

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    gate drive ic is ir2113 and both controller and ir2113 signal input are 5 v
     
  12. ronsimpson

    ronsimpson Well-Known Member Most Helpful Member

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    Do you have a "dead time" when both MOSFETs are off?
    It is not good to turn Q1 on at the same time you turn off Q2.
     
  13. ronsimpson

    ronsimpson Well-Known Member Most Helpful Member

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    I am looking at you ir2113 and don't understand. I can't find a diode that is shown in the data sheet between pins 3 and 6. There are other things that do not look right. No time now its off to work I go.
     
  14. ronsimpson

    ronsimpson Well-Known Member Most Helpful Member

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    Why C6 and C3 that are (more or less) on the gate of each MOSFET. Remove them.
    Pin 3 & C5 should not go to 15V2. There needs to be a diode from 15V2 to Pin 3 and C5. (high voltage, fast, low current, see data sheet) This why you are killing the gate of the top MOSFET. (the IR2113 might be dead also)

    The supply for LO is from 15V2 and that is OK.
    The supply for HO sits on the output of your two MOSFETs. It swings from 0 to +300 volts. When it is at 0 volts current from 12V2 passes through a diode and charges C4. When the output is at 300 volts the diode cuts loose C4 and allows it to 300 volts. The HO driver lives on the stored current C4. It is not powered by 15V2 at this time. With no diode VB, HO, VS can not to high and something brakes.

    Hope this helps.
     
  15. samuel.sam77

    samuel.sam77 Member

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    dear rons i already removed c6 and c3 ,i am using three separate power source 12V for Ka3525 and 15V1 for High side and 15V2 for low side ..so thats why i did not use bootstrap diode as you mentioned ..is this correct or have to use that diode..?
     

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