Method of controlling a power factor correction stage, a power factor correction stage and a controller therefor

摘要

In order to improve the efficiency of a Power Factor Convertor (PFC) first stage to a AC-DC converter the switching cell is split into two smaller ones (each comprising a switched inductor with an output diode). Below a certain load only one cell is active. The second cell only becomes active, out of phase with the first, but not generally in antiphase, after a predefined load level is surpassed in such a way that above that level the first cell has a fixed on time and the second cell a variable one.