• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 63 subscribers
  • Views 275 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

Original question:

UCC28070A: Fault Detection Output

UCC28070A: Using External Peak Current Detection

Kazuki Itoh
Genius 10760 points
Part Number: UCC28070A
Other Parts Discussed in Thread: UCC28070

My PFC system needs external overcurrent detection output.

In order to implement it with UCC28070A, I'm going to make PKLMT voltage very large, and tie external overcurrent detector output to PFC Enable (See 7.3.13 on the datasheet).

One of the concerns of this method is propagation delay of the over current protection will be larger.

Could you please tell me what will happen when propagation delay is large?

How long delay will be tolerable for the PFC?

Best regards,

Kazuki

  • 0
    TI__Expert 3460 points
    Kazuki,

    1, How long is the delay time?
    2, Q: How long delay will be tolerable for the PFC?
    A: It depends on the PFC inductor and mosFET design margin. you have to consider if the inductor is saturation during the delay time.
    you also have to consider if the mosFET current stress is under the max spec during the delay time.
    in addition, you have to care the max voltage of ucc28070 pin CSA CSB.
    3, I think you need to test the OCP function under all conditions to confirm your delay time .


    thanks
  • 0 in reply to Bliss Zhou
    TI__Expert 3460 points
    Hi Kazuki，

    I haven’t heard back from you, I’m assuming you were able to resolve your issue. If not, just post a reply below (or create a new thread if the thread has locked due to time-out)

    thanks