| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a switching power supply that detects an overcurrent state by a frequency-voltage converter when a load is driven by an AC power to protect the load against an overcurrent. <P>SOLUTION: The switching power supply comprises: a switching element that receives a DC voltage from a DC power supply; a control unit for switchably controlling the switching element; a converter transformer having a primary winding to which the switching output from the switching element is supplied and a secondary winding in which an AC voltage is excited by the switching output; a load circuit which is connected to the secondary winding of the converter transformer and to which the AC voltage is supplied; and an overcurrent protection circuit that includes a frequency-voltage converter for converting the frequency of the AC voltage excited on the secondary winding into a voltage and controls the control unit when the output voltage of the frequency-voltage converter becomes a predetermined voltage or more to suppress the switching output. <P>COPYRIGHT: (C)2011,JPO&INPIT |
