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ADUM4135 Driving parallel SiC Mosfets

Category: Hardware
Product Number: ADUM4135

For a high current battery charging application, we need to parallel two SiC Mosfets for each of H-bridge switches. We are using ADUM4135 as isolated H-bridge drivers.

How can we drive the parallel combination with ADUM4135?

This gate driver requires to directly sense the Gate pin of the Mosfet. However, as the general rule, we should not short the Mosfet Gate terminals.

Is there any way out? Can you please suggest a schematic?

Or, we should drive the Mosfets by dedicated ADUM4135 ICs? Can we guaranty the simultaneous turn-on, turn-off in that case?

Thank you.

Parents
  • Hi dip10,

    You can use the following arrangement.
    This is the typical configuration used in power modules where multiple SiC dies are connected in parallel.
    You'll need to find the smallest resistors value that ensure stability depending on the SiC you're using.
    The lower the value of these additional resistors, the better the performance of the internal Miller clamp.
       

    Regards,

Reply
  • Hi dip10,

    You can use the following arrangement.
    This is the typical configuration used in power modules where multiple SiC dies are connected in parallel.
    You'll need to find the smallest resistors value that ensure stability depending on the SiC you're using.
    The lower the value of these additional resistors, the better the performance of the internal Miller clamp.
       

    Regards,

Children
  • Thank you for the suggestion. This is doable.

    Can you please provide some idea to find a ballpark value of the additional resistances?

    My guess : for each Mosfet the Gate capacitance remaining same, the additional resistance should be half that of Rgon and Rgon itself should also be halved.

    For single Mosfet, we find Rgon = Rgoff = 2.7Ohm provides good turn-on, turn-off characteristics.