| 摘要 |
PROBLEM TO BE SOLVED: To provide a physical quantity sensor capable of checking, by own-self, a failure and deterioration of a characteristic in a system including a plurality of detecting elements, with simple constitution. SOLUTION: The physical quantity sensor includes a sensor part 1 with a frequency varied in response to a physical quantity, and a failure detecting part 30 for detecting the failure of the sensor part 1, the failure detecting part 30 includes an LFO 31 for supplying a low-frequency signal to the sensor part 1, a differential amplifier 33 and a comparator 34 for comparing an output signal from the sensor part 1 with the low-frequency signal in the LFO 31 and for outputting comparison results therein, a switch circuit 32 disposed between an output line of the sensor part 1 and the differential amplifier 33, and a control circuit 35 for controlling an operation of the LFO 31 and ON/OFF of the switch circuit 32, based on an external signal, and for detecting the presence of the failure of the sensor part 1, based on the comparison results from the comparator 34. COPYRIGHT: (C)2009,JPO&INPIT
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