| 摘要 |
Provided is a power factor correction circuit, which includes a rectifier circuit 20 that rectifies voltage of an AC power supply 10, a series circuit of an inductor 31 and a semiconductor switch 33 that is connected between output terminals of the rectifier circuit 20, and a series circuit of a diode 34 and a smoothing capacitor 35 that is connected to both ends of the semiconductor switch 33, and in which a load 40 is connected to both ends of the smoothing capacitor 35, so that the power factor on the input side of the rectifier circuit 20 is corrected by the switching operation of the semiconductor switch 33. This power factor correction circuit includes a control circuit 70 that makes switching frequency of the semiconductor switch 33 variable, and the control circuit 70 controls the switching frequency of the semiconductor switch 33 such that the switching frequency becomes the maximum when the ripple of a current flowing through the inductor 31 becomes the maximum. According to this power factor correction circuit, the normal mode noise can be reduced, and the size of a filter circuit 15 can be decreased. |
