Power factor correction circuit

A power factor correction circuit comprising:

• an inductor configured to receive an input voltage and supply an output voltage;
• a power switch connected to the inductor and configured to control an input current flowing through the inductor;
• and
• a switch controller configured to receive a feedback voltage including information on the output voltage and an auxiliary voltage including information on a voltage of the inductor and control an on/off operation of the power switch,
• wherein the switch controller is further configured to:
• operate in a first mode when the feedback voltage is less than a reference voltage,
• operate in a second mode when the feedback voltage is greater than the reference voltage,
• increase an on-time of the power switch as the feedback voltage approaches a target voltage of the output voltage in the first mode, and
• maintain the on-time of the power switch constant in the second mode.