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Replace igbt with mosfet

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  • Replace igbt with mosfet

    Hi everyone.I want to replace an igbt with a N channel mosfet. So I thought that max collector emitter voltage corresponds to max drain source voltage ,the collector current corresponds to drain current.
    About the pins,I think that collector correspcors to drain,emitter corresponds to source and the gate corresponds to the gate of course. Is this replacement possible.Thanks

  • #2
    I want to replace an igbt with a N channel mosfet
    I wonder why.

    There are essential differences between IGBTs and Mosfets.

    The circuit may not be suited for a Mosfet.
    Last edited by Helmholtz; 11-06-2020, 03:59 PM.
    - Own Opinions Only -

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    • #3
      I have no igbts plus that they are expensive.But I have many mosfets.They are for lcd tv board. Can you please tell me the reasons why if you can

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      • #4
        IGBTs and Mosfets have different properties and typically require a different gate drive. Just compare datasheets.

        If the circuit would work with a cheaper Mosfet, I'm sure the designer would not have used an IGBT.

        My question would be, what makes you think that a Mosfet would work in an IGBT circuit?
        Last edited by Helmholtz; 11-07-2020, 12:22 PM.
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        • #5
          I think that because they are both voltage controlled devices but the drive is an issue. Look like I will have to find the exact igbts.I need 600volts at 200 amps(pulsed).I wonder why the TV need igbts that big.

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          • #6
            You have NOT told us what the IgBT will be switching nor shown the schematic, how can we answer?

            Except saying "no" of course.
            Juan Manuel Fahey

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            • #7
              J Μ Fahey I don't have the schematic nor I can find it. All I Know is that they are from a lg TV on a board called Y sustain board.I just found out that those igbts (gt30j124 and gt30f124) are dead (DMM showing short circuit) and I need to replace them.
              Believe me I know it may be hard to answer with such little information and I am afraid the only thing that can be done is replacement with the exact same igbts.
              If there can be an answer I would appreciate it.If not it doesn't matter. I have also read that Y sustain board has to do with the Y axis of the screen and that it actually drives/amplifies the weak signal that the mainboard(includes the receiver etc)has generated.
              Thanks a lot again for your interest and for your time.

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              • #8
                From IXYS:

                "The main advantages of IGBT over a Power MOSFET and a BJT are:

                1. It has a very low on-state voltage drop due to conductivity modulation and has
                superior on-state current density. So smaller chip size is possible and the cost
                can be reduced.

                2. Low driving power and a simple drive circuit due to the input MOS gate
                structure. It can be easily controlled as compared to current controlled devices
                (thyristor, BJT) in high voltage and high current applications.

                3. Wide SOA. It has superior current conduction capability compared with the
                bipolar transistor. It also has excellent forward and reverse blocking
                capabilities.

                The main drawbacks are:
                1. Switching speed is inferior to that of a Power MOSFET and superior to that of
                a BJT. The collector current tailing due to the minority carrier causes the turnoff
                speed to be slow.

                2. There is a possibility of latchup due to the internal PNPN thyristor structure."

                So, 2 & 3 in the advantage column and 1 & 2 in the disadvantages would deserve full consideration if a different part were being considered, To do that requires full knowledge of the design details. In short, stick with the original part.
                Experience is something you get, just after you really needed it.

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                • #9
                  I've used IGBTs in automotive ignition switching applications where a power MOSFET is destroyed in the same circuit due to flyback voltage. I can also dispense with the need for a heatsink. It's more usual to replace in the other direction and sometimes several MOSFETs can be replaced by a single IGBT.

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                  • #10
                    Well, googling a little told me what an Y sustain board is,
                    https://www.google.com/search?client...sclient=psy-ab
                    explained what feeds them (200 ish Volts and 60V), suggested some LG schematics including Elektrotanya, probably not exactly yours but maybe close enough to know what are we dealing with, plus this interesting thread:

                    https://www.electro-tech-online.com/...-specs.157583/

                    and similar ones, worth following.

                    Apparently besides raw IgBYs, some "repair kits" are being offered, the transistor itself plus 2 to 4 parts, I guess they either die or get damaged all together or they are IgBT specific, try to get one of those kits.
                    Click image for larger version

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                    In any case, manufacturers are cheap ass rats, they WILL use the cheapest part possible which does the job efficiently, so if they chose an IgBT instead of a MosFet IŽd use the same.

                    Good luck with your repair
                    Last edited by J M Fahey; 11-07-2020, 11:29 AM.
                    Juan Manuel Fahey

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