基于硅微陀螺的环形二极管电容检测技术研究

Research on Capacitor Detection Technology of Ring Diode Based on Silicon Microgyroscope

针对电容式硅微陀螺在角速率激励下产生的电容变化量在微弱的aF量级,易受外界信号的干扰而湮没的问题,对传统电容检测方法与环形二极管检测方法进行分析对比,采用了电路结构简单、功耗低、易于集成的环形二极管电路完成电容检测,建立了环形二极管电容检测电路的数学模型,分析其参数对检测电路输出电压的影响,结果表明检测电容变化量、解调电容以及载波均对差分输出电压产生影响。进行电路设计时应同时考虑非线性及灵敏度的影响,保证动态灵敏度最高的范围内尽可能增大解调电容,有效改变电容转换增益的非线性,输出与角速度成线性关系的电压信号。

For the capacitive silicon microgyroscope,the capacitance change caused by the typical angular rate excitation is weak in the aF magnitude,which is vulnerable to the interference of external signals.The article analyzes and compares the traditional capacitance detection method and the ring diode detection method.The ring diode circuit with simple circuit structure,low power consumption and easy integration is used to complete the capacitance detection.The mathematical model of the loop diode capacitance detection circuit is established,and the influence of its parameters on the output voltage of the detection circuit is analyzed.The result shows that the capacitance change and solution are detected.Both the modulation capacitor and the carrier have an effect on the differential output voltage.When designing the circuit,the influence of nonlinearity and sensitivity should be considered at the same time,the demodulation capacitor should be increased as much as possible within the range with the highest dynamic sensitivity,the nonlinearity of the capacitance conversion gain can be effectively changed,and the voltage signal linearly related to the angular velocity can be output.