| 摘要 |
<P>PROBLEM TO BE SOLVED: To make a capacitor compact in size by preventing an increase of a ripple voltage of the capacitor in a smoothing circuit, and to reduce the cost of the capacitor, in a power supply circuit which performs PAM control by using a switching element. <P>SOLUTION: The power supply circuit includes a bridge circuit (12) of diodes (D1 to D4) for commutating AC power, and the two capacitors (C1, C2) connected in series to each other, and also includes the smoothing circuit (13) connected to the output side of the bridge circuit (12), and a PAM control part (15) which switches the switching element (S) at prescribed timing. The PAM control part (15) includes a phase difference detection part (15d) which detects the displacement of a phase of a PAM waveform on the basis of a PAM current flowing to the switching element (S), and a phase correction part (15e) which corrects a phase of the PAM waveform so that an input current approximates a sine wave. <P>COPYRIGHT: (C)2010,JPO&INPIT |
