The continuous-discontinuous conduction boundary of a boost PFP fed by universal input

This paper analyzes the continuous-discontinuous conduction boundary path of a boost power factor preregulator (PFP) fed by universal input. Former publications do not study the possible and undesirable continuous-discontinuous conduction traverse (or vice versa) if the boundary curve is not considered. The results of the critical conduction parameter of a boost converter as a PFP are extended to consider universal input. We find that the continuous conduction range of operation is always assured by designing for the greater RMS input voltage value. Most important, it is shown that the design point of a discontinuous boost PFP fed by universal input is a function of the output voltage/input voltage ratio M. Some design examples and simulations complete the analysis