• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 63 subscribers
  • Views 40 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.

UCC28064A: About the phase difference between channel A and channel B

shibanoki.takashi
Prodigy 50 points
Part Number: UCC28064A

Tool/software:

Hi 

We are activating interleaved PFC with "UCC28064A".
When I take out the electric current of rated load, the difference between A-phase and B-phase is 180 degrees and the PFC works properly.
However, when I take out less electric current than the rated load, the PFC works, but the phase difference is smaller than 180 degrees.
Is this correct movement?

  • 0
    TI__Mastermind 29370 points

    Hello Shibanoki-san, 

    The phase-shift between A-phase and B-phase of the UCC28064A controller is maintained by an internal Phase-Locked-Loop (PLL) circuit.  
    The target phase shift is 180 degrees, but the PLL cannot keep it perfectly at 180, and the shift may vary to less than 180 as line and load conditions change.  

    Usually, the phase-shift error is small at lower switching frequencies which is typical at high load.
    Lower load raises the frequency and PLL phase error may increase, so phase difference can be smaller than 180 degrees.

    So, some error from 180 degrees is normal, but the amount of deviation can vary from part to part and has not been quantified.

    Regards,
    Ulrich