| 摘要 |
<p>PURPOSE:To certainly detect the abnormality of a current control element even when a microcomputer has got out of order, by detecting the abnormality of the current control elements on the driving voltage of the current control element to control a current flowing in an electric motor and the voltage at the connecting points of the current control elements. CONSTITUTION:A temperature sensor 5 or the like for detecting the temperature of an electric motor 8 and of FET 12, 12', 13, 13' serving as a current control element gives each detection signal to a microcomputer 6. On the other hand, an abnormality detecting logic circuit 43 is composed of exclusive 'or' circuits 17, 18, AND circuits 19, 20 and a OR circuit 21. At the time of requirement, the output of the exclusive 'or' circuit 17 and the output level of the AND circuit 19 are severally set to 'L' on the relation of voltage at each of points A-C, A'-C' to turn off a transister 15 for turning off a rely 9. Thus even when the microcomputer 6 has got out of order, the abnormality of FET 13, 13' can be judged for stopping current supply to the motor 8.</p> |
