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  1. #61
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    Re: 1.5kw DC to DC Boost Converter Circuit

    yes, a snubber is an R in series with a cap.



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  2. #62
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    Re: 1.5kw DC to DC Boost Converter Circuit

    Yes
    output diodes, on my secondary side of transformer of the bridge rectifier?
    output diodes are typically those diode on the output side of the transformer ...



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    Re: 1.5kw DC to DC Boost Converter Circuit

    Mosfets got burnt again after connecting snubber circuit.



  4. #64
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    Re: 1.5kw DC to DC Boost Converter Circuit

    how are you heatsinking the fets?



  5. #65
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    Re: 1.5kw DC to DC Boost Converter Circuit

    I have all the mosfets on a large heat sink and all of them insolated with mica from the heat sink, but after putting the snubbers on they did Not even run to get hot. It's almost like they just shorted or got shoot through. I think the ringing I'm worried about is not to bad without the snubbers.
    I've had it running like that for a while on 800 to 1000 watt and everything was looking normal. Heat sink got up to 45 degrees Celsius.
    I'll post another scope reading once I have it running to see if I should be worried.



  6. #66
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    Re: 1.5kw DC to DC Boost Converter Circuit

    Mica and thermal paste is not rated for more than 100V, so check the insulation to the heat-sink in case you knocked it and things got shorted out ...

    - - - Updated - - -

    Also check the snubber ckt is connected from Drain to Source ( not gate ) --/\/\/\/\-----|| ---- in series ...

    and that the snubber caps are rated high enough in volts - and the resistors are big enough not to go short ...



  7. #67
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    Re: 1.5kw DC to DC Boost Converter Circuit

    Click image for larger version. 

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    This is what I meant with the ringing, and should I add snubbers to this.



  8. #68
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    Re: 1.5kw DC to DC Boost Converter Circuit

    I wouldn't worry about that too much - - is that the gate drive ... ?



  9. #69
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    Re: 1.5kw DC to DC Boost Converter Circuit

    Yes, it's the gate drive.



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  10. #70
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    Re: 1.5kw DC to DC Boost Converter Circuit

    OK - it's pretty ugly gate drive - but cannot say more without a schematic ...



  11. #71
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    Re: 1.5kw DC to DC Boost Converter Circuit

    http://2.bp.blogspot.com/-IGrcj4RjyY...cuit+50kHz.png
    http://4.bp.blogspot.com/-Lld4HStSKl...IR2110+-+7.png

    These are my exact circuits but only the sg3525 are driving my 2xIR 2113 ic.
    How can I try and improve the gate signal on the fall time, or is this my reverse mosfet diode that's showing the spike on the turn of side, I did try and use snubbers but it does not remove the spike.



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