| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a protection device for load circuits that surely shuts off a load circuit when a chattering short circuit or a layer short circuit occurs by detecting a wire temperature rise. <P>SOLUTION: When a current flowing into a load 4 is increasing, a rising temperature of a wire is calculated by using each different method depending on whether the current is a normal current or an overcurrent. When the current flowing into the load 4 is decreasing, a falling temperature of the wire is calculated by using each different method depending on whether the current is the normal current or the overcurrent. Accordingly, it is possible to calculate a wire temperature by separating a period during normal operation from an overcurrent period during which a chattering short circuit or a layer short circuit occurs or the like. It allows to highly accurately detect a wire temperature rise. Consequently, it is possible to protect load circuits. <P>COPYRIGHT: (C)2009,JPO&INPIT |
