Patent ID: 8427853

Claim:
A power factor correction converter comprising: a rectifier circuit that rectifies an alternating-current voltage input from an alternating-current input power supply; a series circuit that is connected to the rectifier circuit and includes an inductor and a switching element; a rectifying smoothing circuit that is connected in parallel with the switching element; a switching controller that controls the switching element such that an input current input from the alternating-current input power supply is caused to have a similar shape to the alternating-current voltage; a current detector that detects a current flowing through the inductor; and an operation mode determination unit that determines whether an operation mode is a continuous current mode or a discontinuous current mode; wherein in a case where the operation mode is the continuous current mode, the switching controller controls the switching element such that an average value of the current flowing through the inductor detected by the current detector changes in the form of a sine wave and in a case where the operation mode is the discontinuous current mode, the switching controller controls an on period of the switching element to be constant throughout a voltage change period of the alternating-current input power supply such that a peak value of the current flowing through the inductor changes in the form of a sine wave; and when L denotes an inductance value of the inductor, Vin denotes the alternating-current voltage, Vo denotes an output voltage of the power factor correction converter, Ton denotes the on period and Toff denotes an off period of the switching element, and a detection value of a current sampled by the current detector at a midpoint of the on period of the switching element is denoted by I Lav , when I Lav −(½)×{(Vo−Vin)/L}×Toff is positive, the operation mode determination unit determines that the operation mode is the continuous current mode and when I Lav −(½)×{(Vo−Vin)/L}×Toff is negative, the operation mode determination unit determines that the operation mode is the discontinuous current mode.