However, both the drive and detect channels are implemented on a PCB as well as the resonator frequency is detected by a PLL. In order to overcome the aforementioned need for an extra temperature sensor and system size issues, a concept design using the FPGA-based compensation method was discussed by the authors of [15] and a whole integration system is proposed in this study.In this study, the TBD behavior of the fabricated micro-gyroscope is investigated and an active compensation system is integrated in the ASIC to suppress the undesired TBD. First, the design and fabrication principles of the micro-gyroscope are described in Section 2. Moreover, the details of the designed CMOS drive/readout circuit are addressed in Section 3.

Section 4 discusses the temperature-dependent characteristics of the micro-gyroscope and deals with the proposed active thermal compensation system. Then, the behavior of the micro-gyroscope system with the proposed active thermal compensation system is verified by some experimental results and addressed in Section 5. Finally, Section 6 concludes this work.2.?System ArchitectureThe system block diagram of the proposed MEMS-based gyroscope with active thermal compensation is shown in Figure 1. The system comprises three parts: the micro-machined mechanical gyroscope, the analog part and the digital part of the ASIC. In this study, the micro-gyroscope is a vibratory type gyroscope, which consists of a resonator in the X-axis direction and a Coriolis accelerometer in the Y-axis direction.

As the external angular rate about Z-axis is presented, the Coriolis accelerometer would respond to oscillations due to the resonator and is driven all the time into resonance. Moreover, the designed drive/readout ASIC consists of a driving-loop circuit to drive the resonator Cilengitide into resonance, a trans-impedance amplifier (TIA) to detect the Coriolis signal, as well as a gain/offset trimming ADC to adjust this output, a charge pump to supply high DC voltage for polarization and frequency adjustment, and the digital signal processing circuit for digital frequency synthesis and I2C interface communication. Furthermore, the proposed active thermal compensation system is integrated in the digital part of the ASIC to compensate the bias-drift due to the varying temperature.Figure 1.Block diagram of proposed MEMS-based gyroscope system.2.1.

Dynamics of MEMS Vibratory GyroscopeThe equivalent 2-DOF mass-damper-spring system shown in Figure 2 is used to describe the dynamic behavior of the MEMS vibratory gyroscope. The resonator and Croiolis accelerometer are driven to vibrate about the X-axis for the drive mode. The sense mode of the Coriolis accelerometer is responded to vibrate about the Y-axis if the exerted angular rate about the Z-axis is presented.Figure 2.Equivalent 2-DOF mass-damper-spring system.