Title :
A digitally controlled MEMS gyroscope with 3.2 deg/hr stability
Author :
Rödjegård, H. ; Sandström, D. ; Pelin, P. ; Hedenstierna, N. ; Eckerbert, D. ; Andersson, G.I.
Author_Institution :
Imego AB, Sweden
Abstract :
The paper describes the implementation of digital feedback loops and digital signal conditioning for the control of vibrating MEMS gyroscopes. Compared to conventional analogue solutions, this implementation improves flexibility regarding algorithms and control parameters. The offset stability is also improved since mixing is performed using digital signals which are free from 1/f noise. The digital system is implemented in an FPGA that is connected to the gyro via an interface circuit. This circuit is a configurable analogue ASIC containing high performance capacitive readout amplifiers, 5th order sigma-delta modulators and analogue feedback recovery circuits. The digital control architecture has been evaluated with a mass-produced silicon-micromachined butterfly gyroscope aimed for the automotive industry. The system shows a white noise-floor of 0.003 deg/(s√Hz) and an Allan variance stability of 3.2 deg/hr.
Keywords :
amplifiers; application specific integrated circuits; circuit feedback; circuit stability; digital control; digital signal processing chips; field programmable gate arrays; integrated circuit design; logic design; microsensors; mixed analogue-digital integrated circuits; readout electronics; sigma-delta modulation; signal processing; white noise; 1/f noise; Allan variance stability; FPGA; analogue feedback recovery circuits; capacitive readout amplifiers; configurable analogue ASIC; digital feedback loops; digital signal conditioning; digitally controlled MEMS gyroscope; interface circuit; offset stability; sigma-delta modulators; silicon-micromachined butterfly gyroscope; white noise-floor; Application specific integrated circuits; Circuit noise; Circuit stability; Digital control; Digital systems; Feedback circuits; Feedback loop; Field programmable gate arrays; Gyroscopes; Micromechanical devices;
Conference_Titel :
Solid-State Sensors, Actuators and Microsystems, 2005. Digest of Technical Papers. TRANSDUCERS '05. The 13th International Conference on
Print_ISBN :
0-7803-8994-8
DOI :
10.1109/SENSOR.2005.1496472
