Anyone knows how IR1150-D2 rectifier circuit with unity power factor works?

I have a controller IR1150-D2 which is a PFC IC for rectifier circuits.
I have done some experiments on it.

I am able to get a perfectly nice sine wave but no voltage regulation.

The losses are very high, with input power of 75W, I just obtain output power of 40W. I am wondering what is the problem there.


Thanks in advance.