| 摘要 |
PROBLEM TO BE SOLVED: To provide an electronic device protecting circuit which can prevent surely an overvoltage from being applied to a secondary battery, a semiconductor element or other electronic devices, and can prevent breakdown, damage, etc., of the protecting circuit itself. SOLUTION: In this electronic device protecting circuit 100, a temperature fuse 7 and a Zener diode 5 are so installed that thermal conduction is mutually enabled. When an overvoltage exceeding a rated voltage is applied to a battery cell 9, a current corresponding to the voltage flows, the Zener diode 5 generates heat, and accelerates fusion of a temperature fuse 7. The current is bypassed to the Zener diode 5 and a positive temperature coefficient resistor 3, and the amount of current flowing in the battery cell 9 is reduced. When a resistance value of the resistor 3 increases, a current flowing in the Zener diode 5 is set to be restrained. |
