| 摘要 |
PROBLEM TO BE SOLVED: To provide a sensor circuit capable of detecting a capacitance change being equal to or lower than a sub-picofarad level to be generated with a vibration in a movable structure of a vibration sensor.SOLUTION: A sensor circuit includes: a capacitance change integration circuit configured such that three or more odd-numbered diodes and a capacitive element are serially connected between a power terminal and a grounding terminal, inverse-phase detection signals are inputted to an anode and a cathode of an even-numbered-stage diode from the power terminal from a vibration sensor where a capacitance is displaced with a differential motion in response to an external vibration, and an output is taken out of a connection point between the last-stage diode and the capacitive element; and a threshold circuit for outputting a result after comparing the output of the capacitance change integration circuit and a predetermined threshold. The sensor circuit is configured to allow a threshold voltage of the diode to be connected to the power terminal of the capacitance change integration circuit to be set to be higher than threshold voltages of the other diodes. |
