A Digitally Controlled MEMS Gyroscope with 3.2 deg/hr Stability

Rödjegård, H., Sandström, D., Pelin, P., Carlsson, M., Bohman, M., Hedenstierna, N., and Andersson, G. I.
Type of publication: 
Conference item

This paper describes the implementation of digital feedback loops and digital signal conditioning for control of vibrating MEMS gyroscopes. Compared to conventional analogue solutions this implementation improves the flexibility regarding algorithms and control parameters. The offset stability is also improved since the 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 siliconmicromachined butterfly gyroscope aimed for the automotive industry. The system shows a white noisefloor of 0.003 deg/sqrt(Hz) and an Allan variance stability of 3.2 deg/hr.

South Korea
Published in: 
The 13th Int. Conf. On Solid-State Sensors and Actuators, Transducers '05, Vol. 1, pp. 535-538.