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介绍了一种基于电磁激励方式,采用基于绝缘体上硅的微电子机械系统(SOI-MEMS)加工方法制作谐振式加速度计及其闭环控制电路系统.传感器芯片制作采用的是SOI材料(10μm+2μm+290μm),利用MEMS加工工艺制作.当外界z轴方向加速度作用于加速度计时,加速度计的两根“H”型谐振梁因受到弯曲应力而产生谐振频率的漂移,通过检测谐振梁频率的变化标定加速度的大小.电磁激励检测方式有利于加速度计的最终闭环控制.闭环电路控制系统主要由增益放大部分、自动增益控制(AGC)电路缓冲系统和移相器组成.测试结果显示,当有1g重力加速度作用于加速度计,闭环电路可稳定输出检测正弦频率信号58.958 kHz,与开环扫频结果一致.加速度计的“H”型谐振梁空气中检测Q值约为400,灵敏度可达584 Hz/g.
A resonant accelerometer and its closed-loop control circuit system based on silicon-on-insulator (SOI-MEMS) processing are introduced based on the electromagnetic excitation mode.The sensor chip is made of SOI material (10μm + 2μm + 290μm), using MEMS processing technology.When the external z-axis acceleration acts on the accelerometer, the accelerometer’s two “H ” type resonant beams due to the bending stress generated resonant frequency drift, by detecting the resonant beam frequency The calibration of the acceleration of the size of the electromagnetic excitation detection method is conducive to the final closed-loop control of the accelerometer.The closed-loop control system mainly consists of gain amplifier, automatic gain control (AGC) circuit buffer system and phase shifter.The test results show that when 1g of gravitational acceleration acting on the accelerometer, the closed-loop circuit can output stable detection of sinusoidal frequency signal 58.958kHz, consistent with the results of open-loop sweep.An accelerometer “H ” type resonant beam in the air detection Q value of about 400, the sensitivity Up to 584 Hz / g.