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ADuM4223 related

Hello RScnell,

Pls clear my doubt regarding the Boost strap gate driver IC ADuM4223.In this IC,I want to use just bottom channel only (i.e) B channel which is directly connected to Vcc (+15V).Using single channel create any issues during operation?My requirement is just to drive a single MOSFET for active snubber application.Kindly provide your suggestions whether i can proceed with my above assumptions.

Best regards

Ramesh P

  • Hello RSchnell,

    Following to the previous post,i am adding the schematic which we would like to proceed for layout.

    We need to drive a single MOSFET using ADuM4223.

    Kindly confirm & suggest - Is it advisable to left open the unused pulse pins(VIA,VOA) as shown in the above schematic?

    Looking forward to your earliest reply,

    Ramesh P

  • Hello Ramesh,

    Your design looks pretty good, but there are some things to note:

    1) It is advised to connect VIA to GND1 if you are not using the VOA channel. This will reduce the chance that VIA could oscillate, which would increase quiescent current on VDD1. This is a rare case, but grounding the input pin is usually simple, so it is advised. You can leave the VDDA/VOA/GNDA unconnected as your schematic shows. That is perfectly fine.

    2) We recommend a little more decoupling capacitance on VDDB. Usually 10 µF is suggested, but 1 µF will work. The result of too low a decoupling capacitance will be a voltage droop on VDDB during turn on of the device.

    3) R15 and R16 looks very large to me. Usually the external series gate resistors are in the range of 3 to 25 Ω. Unless I am reading the notation incorrectly, it looks like R15 and R16 are currently set to 5 MΩ. That would produce a very long rise/fall time, and might not even make it full rail between VDDB and GNDB.

    Otherwise your circuit looks good.

    RSchnell

  • Hello RSchnell,

    Thanks so much for your detailed reply.

    Actually,the value of R15 & R16 is 5.6 ohms which we usually represent it as 5E6

    Rest of the things,we will proceed as per your suggestions.

    best regards,

    Ramesh P

  • Perfect! In my schematic software, 5.6 ohms would be shown as 5R6. Sorry for doubting your numbers.

    RSchnell