| 摘要 |
<P>PROBLEM TO BE SOLVED: To overcome the problem that primary-secondary insulation components such as a photocoupler and a current transformer are required and a switching power supply becomes expensive if a voltage value and a current value of a commercial power supply 1 input to the switching power supply are detected. <P>SOLUTION: The switching power supply has an input voltage detecting circuit 27 for inputting a voltage applied to a rectifying diode 7 connected to the secondary side of a voltage transformer 5 in series and generating a voltage signal Vvp corresponding to the voltage, and a calculation element 10 for calculating a voltage value Vin inputted to the primary side of the voltage transformer 5 on the basis of a voltage value of the voltage signal generated by the input voltage detecting circuit 27. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
