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: Resonant current ringing

Part Number: UCC28950

Hi, team.

The following waveform is a waveform of the voltage across the transformer of the PSFB and the current flowing through the primary side.

The ringing component of the current waveform in the power delivering section form the 1st to the 2nd continues to occur.

Why is it happening?

And I have another question.

I'd like to build a snubber circuit, do you have any suggestions?

Regards,

Kwangwoon.

  • Hi, Kwangwoon

    it doesn't make sense to have such oscillation, could you check the current probe is good first?
    It is better to have Gate signal of OUTA/OUTD, please help to provide.

    Yunsheng

  • Hello,

    The ringing on the primary current is while the transformer is being energized and not during the free wheeling period. 

    Do you have snubber/clamp on the secondary switch nodes?  This ringing is most likely due to secondary side capacitance and leakage inductance.

    The following will bring you to link to the UCC28950 Evaluation module. EVM.  If you have not added a clamp to the switch node please add it.  The following components on the EVM form the clamp/snubber  D4, D6, R6, R7, R8 and C1

    Regards,

  • Hi, Mike O'

    We will proceed with the test by checking the attached data.

    Thank you.

    Regard.