面向陀螺仪应用的两步逼近电容-电压转换电路

A two-step approximation capacitance-voltage circuit design for gyroscope application

设计了一款面向MEMS陀螺仪检测应用的两级电容-电压转换电路.电路采用输入共模反馈技术,降低了寄生电容和增益电容引起的输入共模电压漂移;同时结合相关双采样、补偿电容与保持电容技术,实现了两步逼近的电压输出,降低了增益误差,提高了输出信号频率和精度.电路采用SMIC 0.18μm 1P6M工艺进行实现.后仿真结果表明:电源电压3.3 V,在500 kHz采样时钟频率下,最大处理信号频率20 kHz,电容-电压灵敏度为12.4 mV/fF;在100 Hz带宽内输出信号动态范围为62.3 dB,平均功耗3.85 mW。

For Micro Electro Mechanical Systems(MEMS) gyroscope detection application, a two-stage capacitance-voltage(CV) circuit is presented. The input common-mode feedback technology is used to reduce the input common-mode voltage drift caused by parasitic and gain capacitors. Meanwhile, combined with correlated double sampling, compensation and holding capacitor technology, the two-step approximation voltage output is realized, which decrease the gain error, improves the frequency and accuracy of output signal. The circuit is fabricated by SMIC 0.18 μm 1 P6 M CMOS process. The post-simulation results show that in 3.3 V supply voltage, with 500 kHz clock frequency, the maximum signal frequency is 20 kHz, the C-V sensitivity is 12.4 mV/fF. Within 100 Hz bandwidth the dynamic range(DR) is 62.3 dB, and average power consumption is 3.85 mW.