Title :
0.0354mm 82μW 125KS/s 3-axis readout circuit for capacitive MEMS accelerometer
Author :
Lai, Kelvin Yi-Tse ; Zih-Cheng He ; Yu-Tao Yang ; Hsie-Chia Chang ; Chen-Yi Lee
Author_Institution :
Dept. of Electron. Eng. & Inst. of Electron., Nat. Chiao-Tung Univ., Hsinchu, Taiwan
Abstract :
In this paper, we propose a power/area-efficient capacitive readout circuit for the Micro-Electro-Mechanical Systems (MEMS) sensor of 3-axis accelerometer. The proposed architecture is different from other traditional structures by exploiting true capacitive-to-digital converter (CDC) without Analog-to-Digital Converter (ADC). The proposed CDC can differentiate the bidirectional 125KS/s 80-level accelerations between ±8g and support the 4-level adjustable resolutions of 0.1g/ 0.2g/ 0.4g/ 0.8g for each axis. The proposed readout circuit with 0.0354mm2 area is fabricated in UMC 0.18um CMOS-MEMS process. Experimental results show power consumption is 50uW with 1.8V supply voltage for 1-axis (FOM=3.84pJ), 82uW for 3-axis (FOM=2.1pJ) under 125KHz of sampling frequency and 0.1g acceleration sensitivity for 0.2fF MEMS capacitance change.
Keywords :
CMOS integrated circuits; accelerometers; capacitive sensors; microsensors; readout electronics; 3-axis accelerometer; 3-axis readout circuit; ADC; CDC; CMOS-MEMS process; MEMS capacitance; acceleration sensitivity; analog-to-digital converter; area-efficient capacitive readout circuit; capacitance 0.2 fF; capacitive MEMS accelerometer; capacitive-to-digital converter; frequency 125 kHz; microelectro-mechanical system sensor; power 50 muW; power 82 muW; power-efficient capacitive readout circuit; size 0.18 micron; voltage 1.8 V; Acceleration; Accelerometers; Capacitance; Frequency modulation; Micromechanical devices; Power demand; Sensors;
Conference_Titel :
Solid-State Circuits Conference (A-SSCC), 2013 IEEE Asian
Conference_Location :
Singapore
Print_ISBN :
978-1-4799-0277-4
DOI :
10.1109/ASSCC.2013.6690994
