Patent ID: 8441822

Claim:
A method of controlling a power factor correction stage comprising a first power cell having a first inductor and a first switch and a first output diode, the power factor correction stage further comprising a second power cell comprising a second inductor and a second switch and a second output diode, the method comprising: evaluating whether a control parameter exceeds a threshold value, the control parameter directly related to output power and including one of a sum of a peak current through the first switch and a peak current through the second switch, and a total on-time equal to a sum of an on-time of the first switch and an on-time of the second switch; operating the second power cell, such that the second power cell becomes active and is not in antiphase with the first power cell, if the control parameter exceeds the threshold value; and operating, when the second power cell is operating, the first power cell such that one of: the peak current through the first switch is set to the threshold value less a value equal to a minimum peak-current through the second switch, wherein the threshold value is a maximum peak current through the first switch, and the on-time of the first switch is set to the threshold value less a value equal to a minimum on-time of the second switch.