| 摘要 |
<p>PURPOSE:To drive and control a load and to reduce the number of terminals in a processing circuit detecting the abnormality. CONSTITUTION:The terminal P of the processing circuit 12 realized with a micro computer and the like is periodically changed over for output and input by a changeover switch 15. A level setting part 21 and an output detection part 31 discriminate whether the terminal P is in an output state or an input state from the potential Vp of the terminal P of the processing circuit 12. An output holding part 41 holds driving output till next driving force is derived from the processing circuit 12 in response to the discrimination result. On the other hand, the processing circuit 12 detects the terminal voltage of the load 48 through an abnormality detection part 25 while the terminal P is in the input state, and compares driving output with terminal voltage so as to detect abnormality such as disconnection and short circuit. Thus, the terminal P can be shared for driving the load and detecting abnormality, and the number of the terminals can be reduced.</p> |
