双片集成数字硅陀螺接口ASIC的设计与测试

Design and test of the interface of the dual-chip integrated digital silicon gyroscope ASIC

为实现MEMS陀螺高精度、数字化和小型化,适应惯性导航和测量等领域的应用要求,采用双片集成方式,基于0.5 um的N阱CMOS工艺,设计并实现了一款实用化的MEMS陀螺接口电路.设计了基于高频载波的闭环自激驱动电路和低噪声差分敏感检测模拟前级电路,高频信号将敏感信号调制到高频后与闪烁噪声相加,经过开关相敏解调以及低通滤波后得到低噪声模拟角速度输出,并由集成的高分辨率四阶单环一位sigma delta ADC将模拟信号转化成为数字信号,实现数字化输出的硅陀螺接口电路.测试结果表明:sigma delta调制器的动态范围达到130 d B,陀螺整机量程为±200°/s,带宽为60 Hz,刻度因子为46.45 LSB/((°)·s^(-1));线性度为342×10^(-6),输出噪声为0.004(°)·s^(-1)/Hz1/2,零偏稳定性为3.4°/h.通过电路集成实现了小型化、低成本和角速度数字化精确输出,测试结果与其他相关研究对比表明该结构可以得到很好的性能.

In order to realize the high precision,digital and miniaturization of MEMS gyroscope,which is the application requirements of the field of inertial navigation and measurement,this paper designs and implements a practical MEMS gyroscope interface circuit which adopts the process of dual-chip integration,integrated based on N-well CMOS process of 0.5 μm.The paper introduces the design of analog front-end circuit which contains closedloop self-exciting driving structure based on high-frequency carrier and low noise differential sensitive detection circuit.The high frequency signal modulates the sensitive signal to the high frequency and adds the flicker noise.Through the phase sensitive demodulation and low-pass filtering,the low noise analog angular speed output is obtained.The circuit converts analog signal into digital signal by an integrated high-resolution sigma delta four-order single ring one bit ADC,achieving an interface circuit of silicon gyroscope with digital output.Test results show that the dynamic range of the modulator which bandwidth and scale factor are 60 Hz and 46.45 LSB/(°) · s^(-1),respectively,is up to 130 d B,and the measuring range of gyroscope is ± 200 °/s.The linearity of the modulator with the noise of 0.004(°) · s^(-1)/Hz1/2 is 340 × 10^(-6),and the stability of the zero bias is 3.4 °/h.It enables miniaturization,low cost and precise digital output of angular speed through integrated circuit.Comparison of the test results with other related research also confirms that the structure can achieve good performance.