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UCC2802: UCC2802QDRQ1

Padderick
Prodigy 10 points
Part Number: UCC2802

Hallo together,

I want to know if it is allowed to supply the UCC2802 with 15V current limited by a 100 Ohm resistor so that I can directly supply a SiC-Mosfet with the

15V-output of the PWM-output. In the datasheet it is written that the maximum allowed VCC voltage is 12V, but the turn-on voltage is 12,5 V, what's that?

From datasheet:

In normal operation VCC is powered through a current limiting resistor. Absolute maximum of 12 V applies when VCC is driven from a low impedance source such that ICC does not exceed 30 mA (which includes gate drive current requirement).

So can VCC be higher than 12V when the supply current is limited by an external resistor? 

Is there any suppressor diode inside the UCC2802 which limits the maximum supply voltage? If yes, at which voltage level the overvoltage protection starts to conduct?

Thank you very much.

Best regards,

Patrick

  • 0
    TI__Mastermind 34465 points
    Hi Patrick,
    I agree with you that the UCC2802 data sheet is confusing with regards to its VCC rating.
    The UCC2802 has an internal zener from VCC to GND with a nominal voltage of 13.5V.
    It has a nominal start voltage of 12.5V.
    The part was designed so that it can be started up from a high voltage current limited source.
    Once the ic starts up it can then gets its VCC from bias supply of 12V or less for operation.
    Anyway for your application you will not be able to get a 15V pwm output from the ic.
    You will need an external gate driver with a 15V rail in order to do this.
    The 13.5V internal zener prevents the UCC2802 from operating at 15V.

    Regards
    John
  • 0 in reply to John Griffin1
    TI__Mastermind 34465 points
    Hi Patrick,
    I believe the issue in this post has been answered and since there has been no further communication in over a week I will close this post.
    Please open a new post if you have further issues.
    Regards
    John