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CRD-30DD12N-K reference design : DC primary power supply for the gate driver

gkim
gkim Contributor Level 3
edited January 2023 in General

Hello,

With respect to the reference design of CRD-30DD12N-K, I have a question on the MAIN board.

The DC/DC converter R15P21503D is used as the DC primary power supply for the gate driver.

The negative output of R15P21503D is -3V nominally.

Meanwhile I have two replacements for R15P21503D: QA15115R2 and QA151C3.

The negative output of QA15115R2 is -2.5V nominally whereas the negative output of QA151C3 is -4V nominally.

I am planning to use one of two replacements for R15P21503D as the DC primary power supply for the gate driver.

I wonder which one is better as the DC primary power supply for the gate driver.

QA15115R2 or QA151C3?

Thank you for your consideration.

With regards,

GKIM

Comments

  • FrankWei
    FrankWei Wolfspeed Employee - Contributor Level 2

    Hello

    QA15115R2  is better.

    Regards,

    Frank

  • gkim
    gkim Contributor Level 3

    Hello Frank,

    Initially I supposed that QA151C3 would be better than QA15115R2 because, if QA151C3 is used, the gate driver might be able to discharge the gate capacitance of the SiC MOSFET more quickly with the negative supply of -4V.

    Isn't it?

    Thank you for your consideration.

    With regards,

    GKIM

  • FrankWei
    FrankWei Wolfspeed Employee - Contributor Level 2

    Hi GKIM,

    thank you for your feedback. it is a trade-off on the negative voltage. for most of the cases, -3V is the best, with -4V, it is not easy to let the Vgs spike meet our -8V spec. I prefer QA15115R2 if there are only two options. any way, you can try it on your board and make the final decision. thank you

    Regards,

    Frank

  • gkim
    gkim Contributor Level 3

    Hi Frank,

    Thank you for your review.

    I have understood that the negative output of the DC primary power supply for the gate driver is best when it is -3V.

    Meanwhile I wonder what the maximum voltage level of the Vgs spike is when the negatve supply of -3V is used for this reference design.

    Thank you for your consideration.

    With regards,

    GKIM

  • FrankWei
    FrankWei Wolfspeed Employee - Contributor Level 2

    Hi GKIM,

    Happy new year! sorry for my late response.

    the spike is about -6.4V for this reference design. thanks

    Regards,

    Frank

  • gkim
    gkim Contributor Level 3

    Hi FrankWei,

    I wish you a Happy New Year !

    Thank you for your review.

    Please let me close this discussion.

    With regards,

    GKIM

This discussion has been closed.