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UCC21520: UCC21520 double confirm schematic

Lawrence He
Genius 3280 points
Part Number: UCC21520

Dear.


our client use UCC21520 for EV scooter gate driver to plan , we need double confirm schematic.


if any revise or reserved component and suggestion, Please advise me.

schematic as below:

Sheet1 (2).pdf


Thanks,


Best regards,


Lawrence

  • 0
    TI__Mastermind 33690 points

    Hi Lawrence,

    • The DISABLE pin should not be floated. If not used, please tie the disable pin to GND.
    • The DT pin should be bypassed with a capacitor for optimal performance. I recommend 2.2nF to GND, placed close to the IC pins.
    • The HO/LO gate resistors, power MOSFETs, and other drive components are not included in the file above. Please include these components if you would like them to be reviewed as well.

    What is the switching frequency, bus voltage, and power MOSFET part number?

    Regards,

  • 0 in reply to Derek Payne
    Genius 3280 points

    Hi, Derek Payne

    Please see attached.

    8422.Sheet1.pdf

    Switching frequency: 16kHz,  bus voltage: 86~100V,  MOSFET part number: IPB044N15N5

    If any suggestion, Please advise me.

    Thanks,

    Best regards,

    Lawrence.

  • 0 in reply to Lawrence He
    TI__Mastermind 33690 points
    Hi Lawrence,

    Thank you for linking the gate drive components as well.

    Estimating the total gate charge at 15V for four MOSFETs as about 4 x 150nC, including the 4 x 15nC to drive each 1nF gate capacitor, and the 330nC to drive the 22nF R-C element, the total gate drive power required from any individual channel is 15V * 1µC * 16kHz = less than 250mW, so I am surprised to see BJT buffers used on the outputs. UCC21520 is capable of delivering the same source and sink current as the BJT buffer stage. Furthermore, most of the power dissipation can be concentrated in the external resistors, so the temperature increase in UCC21520 should be small. I think the BJT buffers may not be necessary with UCC21520. Can this structure be replaced with a 10Ω turn-on resistor, a 2.7Ω turn-off resistor, and a turn-off diode?

    With the gate charge required, you have selected a good value for the UCC21520 bootstrap capacitors.

    Overall, you have designed your circuit very conservatively, so I do not have further comments. Good luck with your design.

    Best Regards,