| Summary: | 碩士 === 國立成功大學 === 電機工程學系 === 107 === Accelerometer sensors play an important role in machine malfunction monitoring. In addition, if the sensed signal of accelerometers could be transmitted wirelessly, it could be further applied to internet of things (IoT) applications. This thesis propose an accelerometer-sensing chip, which is a part of a wireless lead-free piezoelectric MEMS accelerometers system. The proposed sensing chip could sense and amplify the original signal from accelerometers, and then filter out noise, including 60-Hz noise. As a result, the whole accelerometers system could have better performance and fit for the need of intelligence machine.
The proposed chip is fabricated by TSMC 0.18μm 1P6M mixed-signal standard CMOS process, and the chip area is 2.44 mm2. This chip consists of four parts: a front-end sensing circuit, two types of filter circuits, and amplifying circuits. Among them, the front-end sensing circuit can change the bias of the signal from accelerometers, which prevents the accelerometers from being damaged by the offset voltages caused by process variations. According to measurement results, the accelerometers system can achieve 100mV/g sensitivity and 1–3 kHz bandwidth.
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