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ISO5500 with active Miller Clamp

Ian Mantle
Prodigy 80 points

Hi

I'm looking to use the ISO5500 to control an IGBT which is in a bit of circuitry that I don't want to switch on during power up.  I don't have a negative rail to use so wanted to use a PNP transistor Miller clamp to the 0V rail.  Has anyone got experience of this type of configuration?

  • 0
    TI__Prodigy 530 points
    Hi Ian,We're looking into this and will get back to you shortly. Thanks
  • 0 in reply to Neeraj Bhardwaj
    TI__Prodigy 530 points
    Hi Ian,
    Do you want to keep the IGBT gate voltage held to zero, when ISO5500 secondary supply is not present? Can you please clarify and share rough schematics to better understand your query. Thanks
  • 0 in reply to Neeraj Bhardwaj
    Prodigy 80 points

    Hi Neer

    I have been looking at the Infineon app note AN-2006-01, particularly Fig 7.

    At turn on I may not have power established on either side of the ISO5500 which is why I am interested in using this type of independent circuit to assure the IGBT is held off under any power up condition.

  • 0 in reply to Ian Mantle
    TI__Prodigy 530 points
    Hi Ian,
    Miller clamp shown in schematics works only when secondary supply is present. As I understand that you want Miller clamp action to avoid switching on of IGBT circuit, even if the secondary supply is not present or during switching on power. Thus, the circuit you are planning to use will not solve your concern.
    To your initial point of planning to use unipolar power/no negative rail , then you can put in Miller clamp to the 0V rail to take care of unintended switching on of Gate of IGBT. Thanks
    Regards,Neer
    PS: If this answers your question, please click verify answer to close this thread