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UCC27712-Q1: Schematic review

Part Number: UCC27712-Q1
Other Parts Discussed in Thread: UCC27712

Hi Team,

I'd like to request the schematic review of UCC27712QDRQ1. It is used on three phase inverter application but the working of this device is abnormal. Please check the schematic below and let me know the review result.

Schematic_UCC27712QDRQ1.pdf

Regards,

  • Hi Jeffrey,

    Thank you for reaching out! After looking through the schematic, there's a few comments I have that could help explain the abnormality you're seeing:

    • The UCC27712 datasheet states that the VDD bypass cap (C7) should be at least 10x the size of the boot cap (C8). Right now, it looks like both capacitors were chosen to be the same size. Section 8.2.2.2 of the UCC27712 datasheet explains how to size your boot capacitor, and the team also has an app note for selecting your bootstrap circuitry: Link.
    • UCC27712 also recommends a small bypass cap between VDD and ground in addition to the larger bypass cap to help reduce noise on the VDD pin:

    • The gate resistors R12 and R16 as well as R17 and R10 are larger than we usually see. This shouldn't be a problem, but will greatly reduce switching speeds and increase power losses.

    Please let me know if you have any questions, or if you are still experiencing issues after implementing these solutions.

    Best,

    Alex Weaver