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IGBT driver update: I called International Rectifier

Discussion in 'Electronic Basics' started by Ignoramus1797, Oct 11, 2005.

  1. I decided to just call IR on the phone. Asked them for a 1,200V gate
    driver for large IGBTs, with negative reverse bias. Spoke to a very
    knowledgeable and helpful engineer.

    He suggested a new chip IR22141SS. This chip has negative reverse
    bias, can drive large IGBTs, has 1,200 V isolation, needs only one
    supply voltage, etc etc etc. He also suggested to read design tip
    DT04-4. I printed the datasheets and the DT, and so far, everything
    looks like this chip perfectly suits my needs, except that it is in
    SSOP and I have a DIP breadboard.

    I think that there are adapters that cam change SSOP24 into DIP.

    http://www.accutekmicro.com/product_detail.cfm?Product=DIP Adapters

    AK24D300-SSOP.8mm 24 Pin SSOP 0.8mm PITCH to DIP


    i
     
  2. And the best part is...

    I called their dealer on the phone, and then they called me back. They
    were able to order me free samples of these chips (2 chips). The rep,
    a super nice woman, said that I should have them on Friday or on
    Monday.

    i

    --
     
  3. Ignoramus1797 wrote...
    Out of the frying pan, into the fire. :>)
     
  4. Pooh Bear

    Pooh Bear Guest

    Be careful with them !

    When the IGBTs fry - the driver normally goes too .

    Graham
     
  5. I will try to be careful indeed. I will make a detailed drawing of the
    relevant part (minus signal generator part) and will post it prior to
    powering it up.

    i
     
  6. Forgot to say. There would not be much to that schematic. The chip has
    almost everything, it just needs a diode, bootstrap capacitor and
    possibly a few resistors.

    i
     
  7. Ignoramus1797 wrote...
    If you think a schematic contains all the relevant information,
    you will find you are sadly mistaken. (Inductance is one key.)
     
  8. You are right. I will try to actually measure inductance of my
    welder. I think that I can do it with the stuff that I have (decade
    resistor, signal generator and voltmeter).

    i
     
  9. Pooh Bear

    Pooh Bear Guest

    I suspect that Win was trying to alert you to layout issues wrt the gate driver
    actually. Read IR's app notes thoroughly !

    Graham
     
  10. You are right, DT04-4 discusses layont of the circuit.

    i
     
  11. Tim Williams

    Tim Williams Guest

    Speaking of IGBTs, I'm thinking about something like this:
    http://www.irf.com/product-info/datasheets/data/50mt060wha.pdf
    for my induction heater. (Problem being IR doesn't show any
    distributors...) If not, then I'm thinking a quad of TO-247
    devices of similar total spec.

    I was also thinking of a cooked-up circuit something like
    http://webpages.charter.net/dawill/Images/Gate Drive.gif
    (yeah, so it has a lot of stages... I don't see another easy solution
    to get it saturating by the floating rails. Oh and I'll do a DC-DC
    converter for the floating supplies) for gate drive, and
    http://webpages.charter.net/dawill/Images/Desat Detector.gif
    for desat detection.

    Any comments?

    Tim
     
  12. ["Followup-To:" header set to sci.electronics.design.]
    On 11 Oct 2005 14:15:58 -0700,
    *chuckle*

    robert
     
  13. Rich Grise

    Rich Grise Guest

    There's a weldor about 5 or 6 feet from my office, welding 1/2" or
    so mild steel. I don't know what amps setting he's using, but
    every time he strikes an arc, my monitor distorts from the magnetic
    field. I don't know how much inductance that translates to, but
    it's almost scary, thinking about how to deal with that kind of
    current/volts/transients with semiconductors. And it's not
    power line droop - the image actually twists! =:-O

    Good Luck!
    Rich
     
  14. I have a small desk fan sitting on my desk, 1.5 ft away from my
    screen. It uses 0.55 amperes of 110V. I need it on cold days because I
    am sitting right under an air conditioning opening blowing hot air.

    Whenever I turn that fan on, the image on my screen begins to shake.

    The reason for relaying this is that I am not sure just how many
    conclusions we can make from seeing image distortion.

    That said, I want to thank you and another poster for making me aware
    of high inductance of the welder and I will try to perhaps delay turn
    off enough to see some cross conduction.

    i
     
  15. Jim Thompson

    Jim Thompson Guest

    I had a funny experience in the early '60's while working on
    alternator regulator designs.

    The control chip sat on the ground tab of the package leadframe.
    Field current, ~5A PWM'd, flowed under the chip. At every switch of
    state all hell broke loose. Turned out that the resulting magnetic
    field moved the BJT base current sideways killing the beta.

    Redesigned the leadframe to have the control chip on its own
    no-current-under stub cured the problem.

    ...Jim Thompson
     
  16. I read in sci.electronics.design that Ignoramus24489
    Depends how much it shakes, but think around 3 A/m or 3.6 uT.
     
  17. Terry Given

    Terry Given Guest

    yep. Yuck!

    always ensure base currents are limited. lest stuff fail during wierdo
    start-up, shut-down or interference conditions. in general, such linear
    circuits have piss-poor performance. actual thresholds vary widely with
    time, temperature and sock colour (or so it seems....). Use a real
    reference voltage, and a proper comparator with suitable hysteresis.


    AIUI you drive the IGBTs with a fixed duty cycle (almost 50%) variable
    frequency square wave. In which case, a transformer + gate resistor
    would do just fine. Or, if you want, use the transformer and a couple of
    diodes + caps to generate the +/- supply rails, *and* drive a
    complementary emitter-follower (thru some Rb) which drives the gate.

    likewise the desat detector is equally yuck. use an LM339, and just
    measure Vc. there are 2 methods: a resistive divider, or an HV diode and
    a pullup to (say) +15V. Either way, note that Vce can be very, very
    negative - even though the IGBT has a reverse diode, there is an
    inductor between it and where you measure Vc.


    Cheers
    Terry
     
  18. Terry Given

    Terry Given Guest

    If I were to develop a unit with those chips, I would get an entire
    *TUBE*. And I would probably use them, too. Until your gatedrive works
    properly, it doesnt work properly. And gatedrives that dont work
    properly cause explosions. Even when you are experienced and careful.

    But there is a *LOT* to be learned from such an exercise.

    Cheers
    Terry
     
  19. Terry Given

    Terry Given Guest

    solid groundplane underneath the circuit. And keep IGBT gatedrive
    connection inductance low - 50nH is really too much, 10nH is better.

    if you use a DIP proto-board, it will go *BANG* the first time you try
    to use it on the welder.

    Cheers
    Terry
     
  20. Terry Given

    Terry Given Guest

    sneaky. bet that wasnt easy to figure out.
    Cheers
    Terry
     
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