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UCC28070: How to improve current distortion and harmonics

user5277039
Intellectual 640 points
Part Number: UCC28070

Dear Ti community

I'm developing PFC by using this IC.

But there are some problems.

The result of the  harmonic measurement is bad.

when middle ～high load, beyond the IEC standard.

I attach  waveform by  oscilloscope.

Yellow is input voltage,red is input current.

I attach my design too.

When there is other necessary information for a solution, please reply.

Please tell me a  improvement plan.

6153.TI.zip

  • 0
    TI__Genius 9790 points

    Hi, 

    First of all, The calculator cannot be opened. 

    here is the improvement method of THD：

    1. Increase Dmax to 0.95

    2. the resistor divider on VINAC and VSENSE pin should be same.

    3. The capacitor on VINAC pin should be close to VINAC pin.

    Another tip: use very stable AC source as input. 

    Regards,

    Yunsheng