| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching power supply that stops safely without being damaged, even if an excessive voltage is applied to the input voltage, and prevents ignition and smoking from occurring in a power supply. SOLUTION: The switching power supply performs conversion to a primary-side DC voltage with a rectifying smoothing circuit connected to an AC power supply, switches a transformer with a switching element and a PWM control IC by using the primary-side DC voltage for inducing power at the secondary side of the transformer, and rectifies and smoothes the power by the rectifying smoothing circuit, to obtain DC output. The switching power supply comprises a primary-side voltage detection means for detecting the primary-side DC voltage via the transformer; an excessive voltage detection means for detecting that the primary-side DC voltage is not less than a setting voltage value; and a stop means for stopping the operation of the switching power supply, when the excessive voltage detection means detects a voltage that is not smaller than the setting voltage value. COPYRIGHT: (C)2008,JPO&INPIT
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