Patent ID: 8749212

Claim:
An on time control circuit for use in a power factor correction (PFC) controller to terminate an on time of a power switch in a PFC converter, the on time control circuit comprising: an amplifier coupled to generate an error signal that is representative of a difference between a feedback signal and a reference value, wherein the feedback signal is representative of an output of the PFC converter; an integrator coupled to integrate a current sense signal that is representative of a current through the power switch to generate an integrator output signal, wherein a gain of the integrator is varied in response to a voltage sense signal that is representative of a value of an input voltage of the PFC converter, such that the error signal is the same for both a first value of the input voltage and a second value of the input voltage; and a comparator coupled to the integrator and to the amplifier to generate a switch power off signal to terminate the on time of the power switch in response to comparing the integrator output signal with the error signal.