• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 503 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.

UCC28070: ucc28070 : relate to calculation Icout _hf

kyeongmin choi
Intellectual 590 points
Part Number: UCC28070

Hello

I am working on 1kw PFC using ucc28070.

Firstly I try to calculate some parameter using UCC28070 Design tool.

But I can't find any formula due to locking in excel sheet.

So I refered to UCC28070 300-W Interleaved PFC Pre-Regulator DesignReview. I can matched between  design tool and I calculated.

I discovered some difference value in design tool relate to Icout_hf

This formula is correct?.. Could you plz check. 6pi  is different compare to bellow formula. (https://e2e.ti.com/blogs_/b/powerhouse/archive/2016/06/14/predicting-output-capacitor-ripple-in-a-ccm-boost-pfc-circuit) Bellow formula is not 6pi but 3pi.  When I use 3pi I can get similar result compare to design tool. 

So I think  3pi is correct value instead of 6pi.  Could plz check which formula correct is. 

thank you

  • 0
    TI__Mastermind 34465 points

    Hello kyeongmin choi,

    The document you refer to , SLUA479B,  has an error in the formula for the calculation of the high frequency current.

    You can see this in certain applications  which  will result in a negative number for  the high frequency capacitor current.

    The Excel calculator tool is correct. It uses this formula:

    Please use this formula in place of the formula from SLUA479B

    I am not familiar with the blog you referenced and so I cannot comment on that particular equation.

    Regards

    John