【作者】 汤佳郁；

【导师】 谭晓昀；

【作者基本信息】 哈尔滨工业大学 ， 微电子学与固体电子学， 2007， 硕士

【摘要】 硅微机械陀螺是一种新型的惯性器件,它在军事应用和民用方面都有着广阔的发展和应用前景。本文首先分析了振动式微机械陀螺的工作原理,在哈工大MEMS中心原有微陀螺ASIC电路的基础上,将单端检测改进为差分检测,并设计了自激驱动电路中的重要模块跨阻放大器。针对单端检测电路存在对共模噪声抑制能力差,对微小电容变化信号的检测能力差,本文提出一种适合电容检测型微机械陀螺的差分检测电路,以克服以上缺点,提高电路及系统的整体性能。其中,积分器电路作为检测电路的前级,其噪声对于整体电路的分辨率影响很大。在本设计中积分器采用折叠式共源共栅全差分运放(具有高速的共模反馈),抑制了共模噪声,检测灵敏度是单端的二倍。检测电路中的一级低通滤波器采用R-MOSFET-C二阶全差分式,与单端检测电路中的有源RC滤波器(电阻为无源)相比,对工艺条件的敏感度不高,同时具有较高的线性度。经仿真,响应曲线与后者的基本吻合,截止频率为13.5kHz,在载波频率处衰减41.01dB。自激驱动中的跨阻放大器是将驱动模态上检测电容检测的变化电流转化为电压信号,并要有合适的增益以放大检测的驱动信号。本设计的跨阻放大器由折叠式共源共栅全差分放大器和可选择的反馈电阻组成。可选择反馈电阻是由MOS开关和工作在线性区的MOS电阻组成,通过外加电压控制MOS开关实现了在跨阻放大器这一级的电路放大倍数的可调性。经Hspice仿真,在输入角速度为1o/s,单端检测的检测灵敏度为7.25mV/o/s。采用差分检测后,其检测灵敏度15.82mV/o/s,较好地提高了检测灵敏度。更多还原

【Abstract】 Silicon micromechanical gyroscope is a new type of inertial sensor, in both civil and military areas, it is studied widely and deeply for its broad foreground of evolution and application. The fundamental principle of vibration micromechanical gyroscope is analysed first. Grounded on the initial ASIC of micro gyroscope of MEMS center, single ended sense circuit is improved to differential sense circuit. And the important block trans-resistrance amplifier of self-excitated drive circuit is designed.Single ended sense circuit has some disadvantages that are poor common-mode noise rejection and poor sensing capacity for small capacitance. So this paper presents a differential sense circuit which is used to capacitive frame gyro. This circuit can improve the performance of the total circuits and the system. As the former stage, the noise of the integrator has a bad influence on resolution. A folded-cascode fully differential op amp is used for integrator with“fast sensing”common- mode feedback circuit. Differential sense circuit rejects common-mode noise and provides a larger sensing sensitivity. R-MOSFET-C two order fully differential lowpass is used in 1st stage of sense circuit. Compared to active-RC filter with linear resistors, it’s request for processing is not very rigorous, while have higher linearity. The IC is simulated. Frequency response of R-MOSFET-C filter tally with active-RC filter. -3dB frequency of the filter is 13.5kHz, attenuation of frequency response is achieved -41.01dB at the frequency of carrier wave.Trans-resistrance amplifier in drive circuit is used for current to voltage conversion, while provides appropriate gain for amplify drive signal. Trans-resistrance amplifier uses a folded-cascode fully differential op amp with a variable resistor in feedback. The variable resistor is implemented using a MOS switch and a MOS device operating in the linear region. Depending on the control voltage at MOS switch, trans-resistrance amplifier implements adjustable gain.The IC is simulated by Hspice. When the input angle velocity is 1°/s, sensitivity of the output of single ended sense circuit is 7.25 mV/°/s. The sensitivity of differential sense circuit is 15.82mV/°/s.更多还原