| 摘要 |
<P>PROBLEM TO BE SOLVED: To achieve high accuracy of PAM (Pulse Amplitude Modulation) control. <P>SOLUTION: A power supply circuit includes a switching element (S) for short-circuiting an output power of a diode bridge circuit (12), a zero cross detection section (5a) for detecting a point at which input voltage is not more than a reference value, a timer section (5d) for starting count upon detection, and a PAM waveform output section (5c) for allowing the switching element (S) to switch at a predetermined timing by using the count so that the input current may have a waveform of a sinusoidal wave. The circuit includes a correcting section (5e) for correcting an initial value of the count of the timer section (5d) for a difference between a detection interval of the zero cross detection section (5a) and a mean value so far if the difference occurs. <P>COPYRIGHT: (C)2009,JPO&INPIT |
