Bridgeless pfc boost charger switching implementation

[Jediniah24]

Pls I am confused as to what switching waveform to use to achieve pfc as close to 1 as possible .
I have ac coming in do I switch in an halfsine waveform for each half cycle or do I switch I an inverted halfsinewavefor for each half cycle . Pls ca someone explain to me . I want to achieve an efficiency such that at everypoint in the input ac voltage voltage is boosted for my charger . For example at 1v of the input ac my dutycycle has to be at the highest and at the peak of the input voltage my dutycycle has to be least ....this behavior can only be achieved by the inverted halfsine switching but what I see mostly online is an halsine waveform of current for pfc chargers

 

[WHONOES]

Have a look at Power Integrations PFS7523-7529/7533-7539 HiperPFS-3 Ic's. PFC is provided by one iC. Everything you need to accomplish PFC, apart from an inductor and some resistors capacitors and a diode bridge, is incorporated.

 

[Delta Prime]

Is this homework?

Bridgeless power factor correction
can suppress or limit conduction losses that a input bridge rectifier introduces to the circuit.
More information is needed.
please provide a link & documentation of the information you have researched please.