IGBT & gate driver 555 problems

Discussion in 'The Projects Forum' started by bmrdixon, Mar 29, 2010.

  1. bmrdixon

    Thread Starter New Member

    Mar 18, 2010
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    0
    Im made a 14vdc power supply (almost)

    Okay i got an igbt part num. CM400HA-24 i got 17vac smoothed and rectified to 22vdc and run that into the collector....a 555 timer is going at 20khz into a tc4422 driver....output of the tc4422 is going to the gate with 14vdc with respect to gnd....555 timer output is 8.5vdc...Im only getting round 10vdc comming out of the emitter whats wrong..i need 14vdc
     
  2. shortbus

    AAC Fanatic!

    Sep 30, 2009
    4,005
    1,526
    Without seeing your schematic, it sounds like you are trying for a high side switch. You need a high side driver to do this. The driver your using looks like a low side driver. You need to have enough gate voltage above the emitter voltage, not measured to ground, to turn the gate on all the way. Just like in a mosfet.
     
  3. bmrdixon

    Thread Starter New Member

    Mar 18, 2010
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    0
    i have a tc-4422 driver which is non-invering...so should i get the tc-4421 which is inverting??
     
  4. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    A regular 555 has a max voltage spec of 15VDC, the CMOS versions 18VDC. Your not exceeding these are you?

    A regular 555 also has a drop from Vcc of 1.2 to 1.4. That is, the highest voltage it will put out is less than Vcc by that amount.

    Have you read this?

    LEDs, 555s, Flashers, and Light Chasers
     
  5. bmrdixon

    Thread Starter New Member

    Mar 18, 2010
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    0
    i prolly have 15 going to the 555
     
  6. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    How about a schematic?
     
  7. bmrdixon

    Thread Starter New Member

    Mar 18, 2010
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    0
    I'm giving up on the IGBT and just order me a QM300HA-24 its a big power transistor module thing with a base so i don't have to mess with gates....anybody want a CM400HA-24?
     
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