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LMG3410R070: Parallelization of 2 devices

Part Number: LMG3410R070

Hello,

We are developing a DAB converter using two LMG3410R070 in parallel for a DC link of 400V (maximum 450V). In the datasheet, you recommended use decoupling inductors in case of parallel. Do you have more information about these inductors? Value, current capability, saturation, a part number even?

In addition to this. Could parallel direct PINS: IN / FAULT / LPM_N/  RDRV / BBSW / VNEG?

There are problems if LDO5V is connected parallel also?

Do you recommend any special circuit layout to improve the behavior of this device in parallel? Moreover than the regular layout found in the application notes.

In our application 2 isolated sources powered the LMG3410R070. Using the SN6505BDBVT, as appears in the documentation of the device. Control signals come from ISO7831FDW, again following the documentation.

Best Regards

  • Hello, thank you for your question. The typical decoupling inductor value that is used is 1 uH. The current capability will depend on the current that is expected in the application- unfortunately we do not have a part number available.

     Direct pins should not be connected in parallel. This is because the source nodes on each of the GaN devices are separated by the inductor.

    We do not have any application notes for parallel devices. We recommend applying the standard layout guidelines for GaN devices not used in parallel.

    An additional note: for parallel device configuration, two separate power supplies and two separate isolators are needed.

    Best Regards,

    John

  • Hello John and thank you for answering,

    Looking your answer, I have another questions: With that configuration, there are no umbalances between devices? And in case to avoid decoupling inductors, can we consider use only on power supply source and isolator? Plus, the decoupling inductors, is commented that is needed in hard-switching applications. Which is the maximum current that you can manage in hard-switching with two devices and no coupling inductors?

  • Hi Miguel, thanks for your question. We have acknowledged your request and will look into this for you.

  • Hi Miguel,

    With a 1uH decoupling inductor, the dynamic current sharing between the two paralleled devices are balanced during the switching transient. For hard-switching conditions, the decoupling inductor is needed, and it requires each power supply/isolator for each GaN device.

    Best Regards,

    John