• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 62 subscribers
  • Views 407 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

UCC28711 EVM VDD Filter?

T Kishi
Genius 4425 points
Other Parts Discussed in Thread: UCC28711EVM-160, UCC28711

Hi

My Customer has question.Please cooperate me.

For UCC28711EVM-160,

R4 and C5 are connected in front of VDD. (22.5Ω and 330nF)

Is there a way to determine this constant?

Best Regard

T Kishi

UCC28711.pdf

  • 0
    TI__Expert 4015 points
    The time constant of a series RC network is R*C.

    How to calculate the Vdd capacitor value is explained in section 9.2.2 of the datasheet.
    A resistor is typically added between the bias winding and the Vdd cap to limit the initial current spike when the auxiliary diode becomes forward biased. The value is not typically critical, somewhere in the range of 4.7R to 47R is fairly normal.
    The larger the value the less leakage energy is rectified onto the bias which can be desirable in some cases, not in others...

    Hope this helps.
    Thanks
    Billy