ELECTROSTATIC CAPACITANCE TYPE ACCELERATION DETECTION APPARATUS AND CALIBRATION METHOD THEREOF

摘要

PROBLEM TO BE SOLVED: To provide a calibration function for adjusting sensitivity and adjusting offset by accurately detecting an electrostatic capacitance between detection electrodes disposed while opposing a weight.

SOLUTION: A capacitance/voltage conversion circuit 403 includes a function for converting a capacitance between one detection electrode and a weight and a capacitance between another detection electrode and the weight into a voltage, and a function for converting a difference between the capacitance between the one detection electrode and the weight and the capacitance between the other detection electrode and the weight into a voltage. An EEPROM 410 stores a sensitivity correction value and an offset correction value. A variable gain amplifier 404 adjusts an output from the capacitance/voltage conversion circuit 403 on the basis of the sensitivity correction value. An offset correction circuit 406 adjusts an output from a demodulation circuit 405 on the basis of the offset correction value. A digital interface 408 writes the sensitivity correction value and the offset correction value into the EEPROM 410.

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