Design of a Digitized Vibration Detector Implemented by CMOS Digitized Capacitive Transducer With In-Plane SoI Accelerometer

In this paper, a digitized vibration detector implemented by CMOS digitized capacitive transducer with in-plane silicon-on-insulator (SoI) accelerometer is newly proposed. The proposed digitized vibration detector is attractive due to the fact that all the circuits and the sensor can be robustly and compactly combined together. A total solution including the continuous-time-voltage (CTV) analog sensing circuits and digitalized interface are proposed in this paper. Based upon 0.35-μm 2P4M CMOS technology with 3 V power supply, all the functions and performance of the proposed CMOS digitized capacitive transducer are successfully tested and proven through measurements and confirmed it to be applied on the in-plane SoI accelerometer. The sensitivity of the proposed CTV analog sensing circuits is 50.488 mV/g and maximum nonlinearity is 2.5% over the excitation of 0.25-5.75-g intensity. The peak signal-to-noise-plus-distortion ratio of the proposed digitized vibration detector is 67.6 dB under excitation of 3.25-g intensity. The proposed digitized vibration detector is suitable for digitized accelerometer applications, such as automobiles, consumer electronics, Wii game player, and so on.