Galvanically Isolated MOSFET/IGBT Gate Drive

Discussion in 'General Electronics Chat' started by ashkarmalik, Jul 7, 2015.

  1. ashkarmalik

    Thread Starter Member

    Jul 1, 2012
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    Hello Peoples,
    I am working on a High Voltage MOSFET/IGBT gate driver that is to be used as a half bridge with independent control signal from a isolated source(M.C.U) . I need to drive high power IGBT 600v @ 100A .With a sampling frequency of 15khz to 25khz.
    The main problem is the availability of off-the-shelf Isolated drivers and the huge cost involved to buy them.
    Could some one through some light on a the Gate driver for our purpose.
     
  2. #12

    Expert

    Nov 30, 2010
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    The first thing that comes to mind is an opto-isolator and a gate driver chip.
    I'm not the best at this design; I can't name the chips right now, but I believe they are fast enough for the job.
     
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  3. ashkarmalik

    Thread Starter Member

    Jul 1, 2012
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    Your Solution would be a good Start up Design.But I think Transformer Coupled Driver with a Dedicated GDT would be a better option .
     
  4. #12

    Expert

    Nov 30, 2010
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    OK. So, what is your question? Looking for a current driven, isolated gate driver?
     
  5. ashkarmalik

    Thread Starter Member

    Jul 1, 2012
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    Exactly!
    You Got the Idea.
    I got this Schematic From Internet,So You Would Get An idea what Configuration I need.
    [​IMG]
     
  6. #12

    Expert

    Nov 30, 2010
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    Now you're completely outside my abilities. Be patient. Smarter people than me will be on site after the sun comes up in the western hemisphere.

    (I don't mean we don't have some great engineers in western Europe, I mean they don't usually log in at this time of day.)
     
    Last edited: Jul 7, 2015
  7. shortbus

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  8. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Although the IR2110 will not isolate the drive logic from the mains powered bridge.
    Vss & COM (13 & 2) must be connected.
    Also with no high side switching the IR2110 is not really needed.
    Max.
     
  9. ronv

    AAC Fanatic!

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  10. ashkarmalik

    Thread Starter Member

    Jul 1, 2012
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    The main Problem is to make a Galvanic-ally isolated IGBT Gate driver for my Controller card.
    So a Discrete system based Gate driver with Transformer coupling is required.[​IMG]
     
    Last edited: Jul 7, 2015
  11. ronv

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    Nov 12, 2008
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    So are you saying you already have a board and need a replacement transformer?? If so which schematic?
     
  12. cmartinez

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    Jan 17, 2007
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    If you want to completely isolate the triggering signal from the mosfet, I suggest you take a look at this circuit designed by @JDT. I've successfully used it before myself, and I believe it's perfectly capable of working at the 25Khz frequency that you want.
     
  13. shortbus

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    I went with those because in the first post he said "half bridge". And to me a half bridge is one high side and one low side switch, correct? One of those "moving goalpost" threads it seems.

    And while not "galvanic" the isolation of those gate drivers are guaranteed to 600V according to the data sheets.
     
  14. #12

    Expert

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    That's the opto-isolator and gate driver I suggested in post #2.
     
  15. cmartinez

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    I really really really need to sharpen my observation skills... that, or maybe I've just had enough for today...
     
  16. #12

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    When the TS isn't very sure about what's available, it gets as bad as a "twenty questions" thread where we try to pry the information out, one question at a time. I don't mind the threads that are driven by ignorance. That is a valid reason for asking.
     
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  17. Lestraveled

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    May 19, 2014
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    I am going to try reading between the lines. I think the TS is looking for a high side mosfet driver that can operate at greater than 100 volts and not be a pain to implement.

    Look at the On Semi NCP5181. It might do what you are looking for. The off the shelf, high voltage, high side, mosfet drivers are not really there yet. (Pretty slow for today's switching speeds.) Look especially at the "Allowable output slew rate".
     
  18. ashkarmalik

    Thread Starter Member

    Jul 1, 2012
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    I think there is confusion on what I want to achieve,So I just Clarify that first.
    I am Working on a Motor Drive With 6 IGBT to be controlled.These IGBT Should Be working in the 20~ 25 Khz Range.
    These IGBT Modules are rated at 600v @100~200A each.Since Supply voltages are high (~150v).So I need to provide Isolation to my Gate driver so as in any Mis-happening these IGBTs Doesn't Blow up my Logic system.This is the reason I want to design a GDT based Isolation and IGBT Driver Circuit.I doesn't have any Schematic of the GDT based Driver circuit.So I am in need of a Good Reference design.
     
  19. Ancel UnfetteredOne

    Member

    Jul 3, 2015
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    I did something similar just last week....galvanically isolated gate voltage using a 'charge pump' design.
    Here's the LTspice of it.
    You'll prob. have to alter the design to suit your voltages.

    Bat PWM Sw Cap.asc

    cruts, helped me with this!
     
    Last edited: Jul 8, 2015
  20. ronv

    AAC Fanatic!

    Nov 12, 2008
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    What we don't understand is why you would rather use a transformer that an opto isolator. Both provide the isolation you are looking for.

    http://www.mouser.com/Passive-Compo...yzf3ke&Keyword=gate+drive+transformer&FS=True


    http://www.mouser.com/new/optoelectronics/optocouplers-photocouplers/high-speed-optocouplers/n-6zsft
     
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