| 摘要 |
PROBLEM TO BE SOLVED: To provide an excessive temperature rise preventive circuit of an electronic controller which has a high heat resistance, high productivity, and high degree of freedom in designing. SOLUTION: In an electronic controller 7, a normal open type thermal switch 9 is inserted between power lines after passing through a fuse 3. When an abnormal increase in temperature of the electronic controller 7 is detected, the switch 9 shorts the power lines and melts the fuse 3 and then opens the power lines and thereby a further increase in temperature is prevented. It is also possible to improve the life of contacts and realize the reduction in size by serially connecting a resistor 11 for limiting current to the thermal switch 9 and thereby limiting the conduction current in the thermal switch 9. In order to simplify the circuit configuration, the thermal switch 9 can be connected between the power lines after passing through the fuse 3 and an element for limiting charging current for a capacitor 6. |
