| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an abnormality detection device which has small-scaled circuit configuration and is also unlikely to be influenced by noise.SOLUTION: In an apparatus 1 for performing low-side drive on an electric load 3 by means of an FET 7, a level discrimination circuit 11 and a voltage application circuit 13 are included in order to detect a disconnection failure of a current path from a battery voltage VB through the electric load 3 to an output terminal 5 and ground short-circuiting of the output terminal 5 in a discriminable manner. The level discrimination circuit 11 discriminates whether a voltage Vo of the terminal 5 is at a high level higher than a predetermined voltage between the battery voltage VB and a ground voltage (=0 V) or at a low level lower than the predetermined voltage and outputs a signal Sb indicating a discrimination result to a microcomputer 9. When a signal Sc of the high level is given from the microcomputer 9, the voltage application circuit 13 applies a failure determination voltage (V1) to the terminal 5. If the voltage Vo is low while the FET 7 is off, the microcomputer 9 operates the voltage application circuit 13. If the voltage Vo is high in such a state, a disconnection failure is determined and if the voltage Vo is low, ground short-circuiting is determined.</p> |
