| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a disconnection detection device of a load circuit capable of detecting disconnection of a load circuit without making a circuit structure large in scale. <P>SOLUTION: Current flowing in an electric wire W1 is detected by a current sensor 16. Based on the detected current, the temperature of the electric wire is estimated. When the estimated temperature of the electric wire reaches a threshold temperature, a protection device 100 forcibly turns off a semiconductor switch Q1. If increase of temperature calculated by an electric wire temperature calculating part 24 is zero even when a fixed time (P1) elapses after the semiconductor switch Q1 is turned on, it is determined that a disconnection fault is occurring in the load circuit. Therefore, there is no need to include many parts for detecting disconnection, and the size of the device can be made small. <P>COPYRIGHT: (C)2012,JPO&INPIT |
