微机械惯性仪表在军事和民用两方面都具有广泛的应用前景，目前我国的微惯性仪表正处于研制阶段，其信号处理电路主要是由传统的分立元件组成，这已经成为进一步缩小体积、减轻重量、降低成本、提高性能的瓶颈，与微传感器较小的体积形成很大的反差，使得微传感器的优势大打折扣。因此信号处理电路尤其是电容读出电路的集成化势在必行。本论文针对微机械惯性仪表的工程应用目的，设计并实现一款低噪声、高性能的电容式传感器接口芯片，并以此为基础实现了微加速度计原理样机。论文主要包括以下内容：自行设计实现了电容读出电路，该电路基于开关电容技术，采用采样电荷结构，并利用相关双采样技术来消除1/f噪声、采样开关噪声和失调电压。该接口电路对寄生电容不敏感，具有很低的噪声水平。在接口电路的电容读出前端电路中特别设计预载电压输入端子，该端子用来实现力平衡闭环微加速度计。设计优化并实现了各后续信号处理电路，成功实现了接口电路带宽及增益可编程、传感器零偏补偿、接口电路功能自测、片内参考电压产生等各项预定功能。设计并实现了一个片载环形振荡器，该振荡器具有面积小、功耗低和振荡频率稳定等特点，结合两相不交叠时钟产生电路，为微加速度计专用集成电路芯片提供正常工作所需要的精确时序，并为片外传感器提供一对大小相等、相位相差180度的激励信号。对微惯性仪表ASIC电路芯片进行了试验研究，实测结果表明：该ASIC电路芯片的电容分辨率约5.4aF，温度敏感度69PPM，噪声基底0.17aF/rt-Hz，在单一5V电源电压下的工作电流小于5mA。在研究微加速度计ASIC电路基础上，详细讨论了闭环微加速度计系统的组成结构和工作原理，分析了其有效闭环负反馈方式和各种PID校正电路的优缺点，设计了片外滞后比例积分校正电路和双激励单预载双反馈的闭环反馈方式，提出了封装内系统的整体方案。基于所研制的ASIC芯片，设计并完成了微加速度计原理样机。对该样机进行的试验研究表明：量程为±15g，灵敏度为650mV/g，非线性度为0.098%，噪声基底为23.17μg/rt-Hz，阈值与分辨率均优于50μg，1小时稳定性为0.33mg。

Micromachined inertial instruments have been widely used in both military and commercial applications. At present, signal-conditioning circuits of the micromachined inertial instrument in China are made up of traditional discrete devices that have been the bottleneck to make instruments smaller, lighter, cheaper and better, when compared with smaller sensor, the advantage is sold at a discount greatly. Therefore, the integration of the signal-conditioning circuits, especially the capacitive readout front-end circuit, is imperative. A low noise, high performance interface circuit for capacitive sensor is designed and implemented in this dissertation according to the demand of project and practicality, and based on it, a prototype microaccelerometer is accomplished. The research of the dissertation includes the following issues:Based on switched capacitor technique, the capacitive readout circuit is put forward, designed and implemented. The sample-charge architecture with correlated double sampling technique to eliminaton 1/f noise, sampling switch noise and offset in the interface circuit is proposed to achieve capacitor-voltage conversion, which is insensitive to parasitic capacitance, has a low noise level. A special preload voltage terminal in the front-end readout circuit of the interface circuit for force-rebalanced closed-loop microaccelerometer is designed, through which the interface circuit can handle preload voltage up to power supply voltage.The following signal-conditioning circuits are designed and optimized to achieve the functions of the interface circuit such as the programmable of the bandwdith and gain, compation of the sensor bias, self-test and generation of the on-chip reference voltage. An on-chip ring oscillator with small area, low power and stable oscillating frequency is designed and implemented, together with the generator of the two non-overlapping clocks to synchronize the operations throughout the whole ASIC chip and to provide the a pair of contrary modulation waves with same amplitude for off-chip sensor. The test results of the ASIC circuits for capacitive inertial instruments indicate that the capacitive sensitivity is about 5.4aF, the temperature susceptibility is 69PPM, the noise floor is 0.17aF/rt-Hz and the power is less than 5mA with a 5V single supply.On the basis of studying on ASIC circuits for microaccelerometer, the composition of structure and operating principle of the microaccelerometer system are discussed in detail. Then, the advantages and disadvantages of the effective feedback ways to implement closed-loop system and different methods of proportional-integral-derivative correcting circuits are analysised, the off-chip lag-proportional-integral controller and closed-loop feedback ways of double actuating signals, single preload voltage, double feedback signals are designed and the system in package solution is proposed. Based on the ASIC chip, a prototype microaccelerometer is successfully designed and developed. The test results of the prototype microaccelerometer indicate that the full scale is ±15g, the sensitivity is 650mV/g, the nonlinearity is 0.098%, the noise floor is 23.17μg/rt-Hz, both the threshold and the resolution are better than 50μg and the stability is about 0.33mg in one hour.