带温度补偿的低温漂石英微机械陀螺接口ASIC设计

ASIC design of micro-mechanical gyro interface of low temperature drift quartz with temperature compensation

本文通过分析石英陀螺的工作原理,设计了闭环自激驱动、低噪声相敏解调原理的接口电路,并研究了驱动力耦合对零位输出造成的影响,以提高石英陀螺的环境适应性。通过研究传感器敏感表头的空气阻尼和谐振频率等方面的温度特性,得出温度对驱动力幅值的影响。进而提出通过驱动力幅值进行温度补偿的方法。对接口电路温度特性以及对陀螺零位输出的影响进行了分析,设计了全温区带宽恒定的运算放大器单元,抑制由于检测信号中高次谐波分量比例变化产生的温度漂移,并在高压N阱CMOS工艺下流片,实现低温漂接口ASIC。在-45℃~85℃的温度范围内对石英陀螺整机进行零位温度循环测试,利用驱动力幅值对零位输出进行三阶拟合补偿,补偿后全温零位温度漂移小于20°/hr(1σ),短期稳定性为5°/hr,输出噪声为0.001°/s/√Hz。

Through analyzing operating principle of quartz gyro,interface circuit of closed-loop self-excited drive and based on principle of low-noise phase sensitive demodulation was designed, and influence of driving force coupling on zero position output was researched to increase environmental adaptability of quartz gyro. Effect of temperature on amplitude of driving force was obtained through researching temperature feature on aspects of air damping and resonant frequency, etc of sensitive header of sensor. Then method of conducting temperature compensation via amplitude of driving force was proposed. Temperature features of interface circuit and influence to zero position output of gyro were analyzed, and operational amplifier unit of constant bandwidth in the whole temperature area was designed to restrain temperature drift due to change of proportion of high-frequency harmonic component in detection signal. The chip was implemented in high voltage N-well CMOS process and interface ASIC with low-temperature drift was achieved. Cyclic test of zero position temperature was conducted on whole machine of quartz gyro in temperature scope of -45℃~85℃ to conduct three-order fitting compensation on zero position output with amplitude of driving force. Zero position temperature drift of whole temperature after compensation was less than 20/hr（1）with short-term stability and output noise respectively as 5/hr and 0.001/s/√Hz.