| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a switching power supply circuit accommodating a wide range of input voltage without a large capacitor. <P>SOLUTION: A switching power supply device is configured with a primary-side circuit which comprises: a rectification circuit for rectifying an input voltage from an AC voltage source; a first capacitor for smoothing a rectified voltage; a second capacitor connected with the first capacitor in parallel and connected with a switch in series, having a lower resistance and a larger capacitance than those of the first capacitor; and a switch control circuit for turning on the switch if a potential difference across the first capacitor is smaller than a predetermined reference value. <P>COPYRIGHT: (C)2012,JPO&INPIT |
