INSPECTION METHOD OF SENSOR DEVICE AND SENSOR DEVICE

摘要

In a reset period of a first stage, a switching circuit is turned on, and high-level driving voltages are output from driving circuits. In a charge transfer period subsequent to the reset period, the switching circuit is turned off, and low-level driving voltages are output from the driving circuits. It is determined whether or not an output voltage of an amplifier circuit in the charge transfer period is included in a normal range. In the inspection of a second stage subsequent to the first stage, in the same manner as in the normal measurement, voltages having opposite phases are output from the driving circuits in the reset period and the charge transfer period, and it is determined whether or not the output voltage of the amplifier circuit in the charge transfer period is included in a normal range.

主权项

1. An inspection method of a sensor device, comprising:
a first step of discharging a capacitor by using a switching circuit and outputting a first driving voltage from both of first and second driving circuits; a second step of releasing the discharge of the capacitor by the switching circuit and outputting a second driving voltage from both of the first and second driving circuits; and a third step of determining whether or not a voltage output from an amplifier circuit in the second step is included in a first normal range, wherein a first inspection stage includes the first step, the second step, and the third step, and the sensor device includes: a sensor unit including a first capacitive sensor element connected between a first driving terminal and a signal terminal and a second capacitive sensor element connected between a second driving terminal and the signal terminal; the first driving circuit configured to output the first driving voltage or the second driving voltage to the first driving terminal; the second driving circuit configured to output the first driving voltage or the second driving voltage to the second driving terminal; the capacitor having an end connected to the signal terminal; the amplifier circuit configured to output a voltage, which is obtained by amplifying a difference between a voltage of the signal terminal and a reference voltage, to the other end of the capacitor so that the voltage of the signal terminal becomes close to the reference voltage; and the switching circuit configured to discharge electric charges accumulated in the capacitor.