ucc28070

There is a good application note and excel design tool that you can use to evalute your design.  You can find them at the following link. 

http://www.ti.com/litv/pdf/slua479b

http://www.ti.com/litv/zip/sluc114

Regards

Hi,all.  We are in process of designing PFC with UCC28070 integrated circuit.Power is 300W, 110V input voltage, 60HZ line frequency,180V Output, 100kHZ switch frequen.

I used the application note and excel design tool, The result  of input voltage(Vin) , input current(Iin) & load voltage waveforms at 1/3 load and power factor is found to be 0.98.

But, the waveforms of   Vds(switch voltage) and Ids(switch current) and IL(inductor current) looks for errors. I hope you may from the waveform to give me some circuit recommendations.

HI,

Where on the sine wave are these waveforms taken? 

They don't make much sense. With 200 volts coming in, the gate turns on and pulls the drain to ground. The current waveform should ramp up in a straight line as long as the gate is high. This is not happening.

Repeat the test with a forth probe on the positive output of the diode bridge.

Regards,

John