Power factor correction circuit accounting for zero crossing delay

A method of controlling a power supply apparatus, the method comprising:

• turning off a second switching element of the power supply apparatus configured to discharge current charged in an inductor while a first switching element of the power supply apparatus configured to charge current in the inductor is being turned on;
• turning off the first switching element while the second switching element is being turned on;
• turning off the first switching element based on a predetermined time being elapsed from a time point when the first switching element is turned on while a sensing voltage is less than a control voltage;
• and
• turning off the second switching element through a second control signal after a predetermined delay time from a time point when a current of the inductor becomes zero such that the current of the inductor becomes negative to provide energy for zero voltage switching of the first switching element.

A power supply apparatus, comprising:

• a power factor correction (PFC) circuit;
• and
• a control circuit configured to control an operation of the PFC circuit,
• wherein the PFC circuit comprises:
• a power inputter configured to receive alternating current (AC) voltage to be rectified;
• an inductor having a first end coupled to a first end of the power inputter;
• a first switching element configured to be turned on and turned off, according to a first control signal, and having a first end coupled to a second end of the inductor;
• a second switching element configured to be turned on and turned off, according to a second control signal, and having a first end commonly coupled to the second end of the inductor and the first end of the first switching element;
• and
• an outputter configured to output a direct current (DC) voltage through an output capacitor, and having a first end coupled to a second end of the second switching element and a second end coupled to a second end of the first switching element,
• wherein the control circuit is further configured to:
• apply the first control signal to the first switching element and the second control signal to the second switching element such that the first switching element and the second switching element are alternately turned on;
• turn on the second switching element through the second control signal after a first deadtime from a first time point when the first switching element is turned off;
• turn on the first switching element through the first control signal after a second deadtime from a second time point when the second switching element is turned off;
• and
• turn off the first switching element through the first control signal based on a predetermined time being elapsed from a time point when the first switching element is turned on while a sensing voltage is less than a control voltage;
• and
• turn off the second switching element through the second control signal after a predetermined delay time from a time point when a current of the inductor becomes zero such that the current of the inductor becomes negative to provide energy for zero voltage switching of the first switching element.