Concepts, Roadmaps and Challenges of Ovenized MEMS Gyroscopes: A Review

The MEMS gyroscope by means of oven control, or the so-called ovenized MEMS gyroscope, isolates the die from the external environment and utilizes a closed-loop temperature control system. It is thought to be important as it does not produce bias, scale factor drift made by thermal variations. Hence, a better temperature stability of the device is expected, which potentially benefits greatly the next generation of high-performance MEMS sensor. Herein, we attempt to provide a comprehensive review of many areas of the ovenized gyros, consisting of principle, key technology, the state-of-the-art results and suggestions. The thermal error mechanism and the importance of temperature control are introduced. The descriptions of the principles and characteristics of both on-chip and off-chip architectures are provided. To suppress heat dissipation at the package level, thermal resistance models based on conduction, convection, and radiation are established and analyzed. In terms of heating drive energy efficiency, comparisons have been made within VCCS (Voltage-Controlled Current Source), V-I (Voltage-to-Current) converters and PWM (Pulse Width Modulation), followed by the analysis of SSP (Single Set Point) and MSP (Multiple Set Point) algorithms. With regards the feedback control system, a systematic discussion on its common temperature detection methods, including CMOS PTAT (Proportional To Absolute Temperature), RTD (Resistance Temperature Detector) and TCF (Temperature Coefficient of Frequency) is presented. The control algorithms and limitations for the temperature control are also presented. At the end, we compared and discussed the most representative ovenized gyros to date, followed by suggestions to future development trends.