Patent ID: RE42946

Claim:
A power factor controller, comprising: a) a circuit configured to determine and/or identify (i) a period of a periodic power signal and (ii) a length of time from a beginning of said period during which a potential is applied to a power conversion switch; b) a voltage calculator configured to determine at least a value of the a peak voltage of said periodic power signal; c) logic configured to calculate a time period to open said power conversion switch in response to (i) said length of time, (ii) said power signal period, and (iii) said value of the said peak voltage; d) a voltage detector configured to determine a zero voltage at an input to a power converter operating on said periodic power signal; and e) one or more counters configured to initiate counting (i) said power signal period and/or (ii) said length of time in response to a zero voltage signal from said voltage detector indicating said zero voltage.