• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 660 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.

UCC28950: transformer saturation

kwangwoon Lee
Prodigy 230 points
Part Number: UCC28950

Hi, All,

A phase shift full bridge converter is being developed using UCC28950.

The waveforms below are the primary voltage and current waveforms corresponding to 20%, 30% of the total load.

The part shown in red looks like transformer saturation, is that correct?

                     20%                                                              30%

A similar waveform appeared when controlling with VMC before, so I thought it was transformer saturation and removed it using 

a DC blocking capacitor.

Can transformer saturation occur while controlling in PMC mode?

If transformer saturation is correct, how to get rid of it?

Thank you!

  • 0
    TI__Guru* 86286 points

    Hello,

    When the design is in peak current mode control it should prevent transformer saturation.  

    Your waveform does not look like transformer saturation.  The saturation of a transformer generally make the current look semi parabolic almost like a trick snow skiing jump.

    So I don't believe your transformer is being saturated.

    The waveform you have circled is during the free wheeling period.  If you were using a current double the inductor ripple current cancelation may cause some of this.

    You may want to study the output inductor current and SR FET currents during this waveform to see what is going on.  I still don't think this is transformer or inductor saturation.

    Regards,