| 摘要 |
PROBLEM TO BE SOLVED: To supply a required current to a load, while protecting the load at overvoltage or overcurrent, to automatically interrupt the load current when the overvoltage or overcurrent continues, and to import restoring function for restoring the interrupted load. SOLUTION: This protective circuit is provided with first and second switching elements, connected in series and reverse polarity and inserted to a load current passage, first and second Zener diodes for detecting overvoltage, third and fourth switching elements to be conducted, when they each exceeds the Zener voltage, and a fifth switching element to be grounded by them. At overvoltage, the fifth switching element is grounded by a current flowing through the third or fourth switching element; the first and second switching elements become non-conductive, and the first or second Zener diode becomes lower than the Zener voltage; the third or fourth switching element is turned off; and the fifth switching element is released from grounded state, and the first and second switching element go into a conductive state to perform a feedback operation for conducting the load current passage. COPYRIGHT: (C)2008,JPO&INPIT
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