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UCC27710: VDD

Takashi Yamaguchi
Genius 13450 points
Part Number: UCC27710

Hi team,

I have a question about UCC2771x.

The d/s mentions that the recommended range of VDD is 20V(max) for IGBT application and 17V(max) for MOSFET application. Could you tell me the reason why the recommended range is different between them?  My customer would use MOSFET and wants to apply 19V to VDD. Is it acceptable?

Regards,

Yamaguchi

  • 0
    TI__Mastermind 23215 points
    Hello Takashi,
    Thank you for supporting the UCC27710 half bridge driver for your customer. There are a couple of considerations with the recommended VDD range for MOSFETs and IGBTs.
    With most MOSFET applications a Vgs of 10V to 12V is adequate to achieve low Rdson and high current capability. With IGBTs the typical drive voltage is higher with 15V being common to ensure low Vce saturation voltage.
    Can you comment why the customer wants to operate the VDD at 19V with a MOSFET?
    The reason for the recommendation is that with high VDD and low gate resistance some MOSFET devices switching transitions can have very high Vds dV/dt in some applications. There can be gate driver concerns resulting from the very high dV/dt conditions. Where IGBTs switching dV/dt is much lower even with higher Vgs voltages.
    We can only recommend that the VDD be operated within the recommended VDD range for long term operation, and stay below absolute maximum for any short term transient condition.
    Is it not practical to limit the VDD to the 17V recommended range?

    Please confirm if this answers your questions , or you can post additional questions on this thread.

    Regards,
    Richard Herring
  • 0 in reply to Richard Herring
    TI__Genius 13450 points
    Hello Richard-san,

    Thank you for the answer.

    Is the concern high switching noise due to the high dv/dt ? Is the concern that the device's HS pin gets damage by the high switching noise ?

    Regards,
    Yamaguchi
  • 0 in reply to Takashi Yamaguchi
    TI__Mastermind 23215 points

    Hello Yamaguchi,

    In the case of higher VDD with some MOSFETs switching, very high dV/dt VDS rise time and high dV/dt ringing can occur on the switch node.

    With high dV/dt on the HS pin, beyond the datasheet specification may cause the driver output to not be in the correct state, or the driver output may have voltage undershoot beyond the datasheet ratings.

    Please confirm if this answers your questions, or you can post additional questions on this thread.

    Regards,

    Richard Herring