Power factor correction converter including input current detecting circuit

A PFC converter comprising:

• a rectifier circuit arranged to rectify an AC voltage input from an AC input power supply;
• a series circuit connected in a subsequent stage of the rectifier circuit and including an inductor and a switching element;
• a rectifying and smoothing circuit connected in parallel to the switching element;
• a switching control circuit arranged to perform on/off control on the switching element so that an average value of an input current input from the AC input power supply has a similar waveform with respect to the AC voltage;
• an on-period current detecting circuit arranged to detect a current flowing through the switching element or the inductor during an on period of the switching element or an off-period current detecting circuit arranged to detect a current flowing through the inductor during an off period of the switching element;
• and
• an input current detecting circuit arranged to detect, as an average value of the input current, a value that is obtained by calculating
• ILav=Is+(Vi/L)×Ton/2 or
• ILav=Is+{(Vo−Vi)/L}×Toff/2,
• where a current value that is obtained by sampling a current detection signal generated by the on-period current detecting circuit or the off-period current detecting circuit at an end point of the on period or a start point of the off period of the switching element is represented by Is, an input voltage input from the AC input power supply is represented by Vi, an output voltage is represented by Vo, an inductance value of the inductor is represented by L, the on period of the switching element is represented by Ton, the off period is represented by Toff, and an average value of a current flowing through the inductor is represented by ILav.

A PFC converter comprising:

• a first series circuit connected in parallel to a load and including a first switching element and a first rectifier element;
• an inductor connected between a connection point of the first switching element and the first rectifier element and a first input terminal of an AC input power supply;
• a second series circuit connected in parallel to the load, including a second switching element and a second rectifier element, and including a connection point of the second switching element and the second rectifier element that is connected to a second input terminal of the AC input power supply;
• a smoothing circuit connected in parallel to the load;
• a switching control circuit arranged to perform on/off control on the first and second switching elements so that an average value of an input current input from the AC input power supply has a similar waveform with respect to an AC voltage of the AC input power supply;
• an on-period current detecting circuit arranged to detect a current flowing through the first or second switching element or the inductor during an on period of the first or second switching element or an off-period current detecting circuit arranged to detect a current flowing through the inductor during an off period of the first or second switching element;
• and
• an input current detecting circuit arranged to detect, as an average value of the input current, a value that is obtained by calculating
• ILav=Is+(Vi/L)×Ton/2 or
• ILav=Is+{(Vo−Vi)/L}×Toff/2,
• where a current value that is obtained by sampling a current detection signal generated by the on-period current detecting circuit or the off-period current detecting circuit at a start point of the on period or an end point of the off period of the first or second switching element is represented by Is, an input voltage input from the AC input power supply is represented by Vi, an inductance value of the inductor is represented by L, the on period of the first or second switching element is represented by Ton, the off period is represented by Toff, and an average value of a current flowing through the inductor is represented by ILav.

A PFC converter comprising:

• a first series circuit connected in parallel to a load and including a first switching element and a first rectifier element;
• an inductor connected between a connection point of the first switching element and the first rectifier element and a first input terminal of an AC input power supply;
• a second series circuit connected in parallel to the load, including a second switching element and a second rectifier element, and including a connection point of the second switching element and the second rectifier element that is connected to a second input terminal of the AC input power supply;
• a smoothing circuit connected in parallel to the load;
• a switching control circuit arranged to perform on/off control on the first and second switching elements so that an average value of an input current input from the AC input power supply has a similar waveform with respect to an AC voltage of the AC input power supply;
• an on-period current detecting circuit arranged to detect a current flowing through the first or second switching element or the inductor during an on period of the first or second switching element or an off-period current detecting circuit arranged to detect a current flowing through the inductor during an off period of the first or second switching element;
• and
• an input current detecting circuit arranged to detect, as an average value of the input current, a value that is obtained by calculating
• ILav=Is+(Vi/L)×Ton/2 or
• ILav=Is+{(Vo−Vi)/L}×Toff/2,
• where a current value that is obtained by sampling a current detection signal generated by the on-period current detecting circuit or the off-period current detecting circuit at an end point of the on period or a start point of the off period of the first or second switching element is represented by Is, an input voltage input from the AC input power supply is represented by Vi, an output voltage is represented by Vo, an inductance value of the inductor is represented by L, the on period of the first or second switching element is represented by Ton, the off period is represented by Toff, and an average value of a current flowing through the inductor is represented by ILav.