| 摘要 |
PROBLEM TO BE SOLVED: To obtain a semiconductor sensor which can be miniaturized by a method wherein a sensor-output control means is installed across a signal amplification means and a sensor output terminal and the output of a sensor result is controlled on the basis of a self-diagnostic result. SOLUTION: A sensor-output control circuit 17 which is composed of a second transistor 24 is installed across a self-diagnostic circuit 15 and a sensor output terminal Vout. A comparator 21 at the diagnostic circuit 15 outputs a normal signal (or an abnormal signal) when is monitoring voltage from a detection circuit-signal amplification circuit 13 is within (or outside) a prescribed range. That is to say, when the voltage is normal, a voltage at 'H' is output, a first transistor 22 is turned on, and the output at a point (a) of the diagnostic circuit 15 is at 'L'. At this time, the second transistor 24 is turned off, and the control circuit 17 outputs the output of the amplifier circuit 13 to the output terminal Vout. When an abnormal voltage is detected, the output of the comparator 21 is at 'L', the output at the point (a) is at 'H', the transistor 24 is turned on, the output of the output terminal Vout is fixed to 'L', and a detection result is not output. As a result, a malfunction can be prevented, it is not required to install an output terminal for self-diagnosis separately, and a semiconductor sensor can be miniaturized.
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