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Original question:

UCC28740: Parameter: AC-DC,Pout:30W;Vin:90V~300VAC; internal MOS cotroller，Isolated or non-isolated。Which PN can meet the...

UCC28740: UCC28740

bhargav goud
Prodigy 160 points
Part Number: UCC28740
Other Parts Discussed in Thread: PMP20533, UCC28056

Hello

Assuming a 20W resistive load for a isolated AC-DC flyback converter based on UCC28740, what would be the power factor?

If the load is being switched continuously will that have an affect on the power factor?

Please suggest.

Thank You!

  • 0
    TI__Expert 8210 points

    Bhargav

    UCC28740 does not have any active power factor correction.  One design we have that did measure power factor is PMP20533, where the PF roughly varies from 0.3-0.5 depending on the operating point.

    The low PF comes from the diode bridge rectifier on the input.  I recommend that you watch the beginning of this video https://training.ti.com/power-factor-correction-pfc-basics to review how the load and operating condition affect PF.

    If you need better PF than what UCC28740 provides, you can either use a passive filter with resistor and capacitor, which can be large and heavy, or add a PFC pre-regulator with one of our PFC boost controllers such as UCC28056.

    Best Regards,

    Eric