| 摘要 |
PROBLEM TO BE SOLVED: To provide an induction load drive circuit capable of accurately detecting existence of abnormality around the induction load and a relay switch without causing enlargement of scale of a circuit in spite of providing the relay switch shutting off electricity carry at a time of abnormality of the induction load. SOLUTION: This drive circuit drives a fuel adding valve 18 through control turning MOSFET 33 on when the relay switch 40 is in on-state. The drive circuit creates monitor signal based on voltage at a point P which is a connection point of the MOSFET 33 and a series circuit composed of the relay switch 40 and the fuel adding valve 18, and detects abnormality of the fuel adding valve 18 based on the monitor signal. The drive circuit changes over ON/OFF state of the relay switch 40 during a period of control turning on the MOSFET 33, and existence of abnormality of the relay switch 40 is detected based on transition of the monitor signal when the relay switch 40 is changed over. COPYRIGHT: (C)2006,JPO&NCIPI
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