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1、摘要I摘 要基于微机械加工技术的传感器是一类很重要的传感器。实现 IC 兼容工艺后，可以将微机械传感器敏感芯片与相应的接口电路集成在同一个硅片上，降低制造成本，重复性与一致性好，具有高的灵敏度和分辨率。电容式传感器是将被测的非电量变化转换为电容量变化的一类传感器，它广泛应用在压力、湿度、温度和加速度等测量中，具有功耗低、灵敏度高、受温度的影响小等优点。MEMS 电容传感器结合了电容传感器和 MEMS 传感器的优点，成为现在传感器领域一个研究热点。随着 MEMS 工艺的逐渐提高，传感电容越来越小，外界物理量引起的传感电容的变化更是微小，这样检测电路就变的相对复杂。传感器的检测精度很大部分被检测电
2、路所限制。本文设计了一种低噪声电容检测 ASIC。本论文的主要的研究工作和成果如下：（1）研究 MEMS 电容传感器工作原理，确定等效模型，根据传感器工作范围、精度要求等确定检测 ASIC 性能指标。（2）根据性能指标，查阅文献，确定检测方法，确定电路原理图。（3）设计检测 ASIC 需要的低噪声放大器，时序控制电路等，完成整体电路晶体管级设计。（4）完成整体电路的版图设计，对版图进行检查和后仿真，确定最终电路形式。送交代工厂流片。（5）对电路进行深入分析，总结不足，提出进一步研究的方向。关键词：MEMS；电容式微传感器；CMOS 运算放大器；低噪声；ASIC；ABSTRACTIIABSTRA
3、CTMicro-machined sensors based on the MEMS technology are very important sensors. These sensors can be fabricated together with their interface circuit on the same silicon substrate. As a result, the cost can be lowered while the sensitivity and the resolution can be improved. A capacitive sensor in
4、cludes a variable capacitor transducer which varies its capacitance according to the environmental parameter. They are widely used in the applications of parameter measurement such as pressure, humidity, temperature and acceleration, etc, comparing with other sensors , the capacitive sensors consume
5、 less power, have less temperature coefficient and higher sensitivity. MEMS capacitive sensors are studied actively since they own the advantages of both MEMS sensors and capacitive sensors.With the fast development of the design and manufacturing level of MEMS, the change of the sensor capacitance
6、becomes much smaller along with the sensor capacitor, complicating the design of readout circuit. Since the sensitivity of the sensor highly depends on the readout circuit, we propose a ASIC for multi-dimension accelerator with low noise in this paper. The main work and achievement are as follows:1
7、Carefully study the working principle of the MEMS capacitive sensors, and determine the equivalent model. Determine the specification of the ASIC by input range and resolution requirements.2 Conduct literature review to determine the topology of this ASIC according to the specification.3 Design the
8、low noise amplifier, timing control circuit, etc. complete the whole device level design.4 Layout of the whole circuit, do DRC/LVS and post-simulation. Extract the GDS file and tape out.5 Thoroughly analyze this circuit to find its drawbacks for further research.Key Words: MEMS；capacitive-micro-sens
9、or；CMOS Opamp；low noise; ASIC;第一章 绪论1目录摘 要 .IABSTRACT.II目录 .III第一章 绪论 .11.1 课题研究的背景 .11.1.1 集成电路设计技术的发展 .11.1.2 MEMS 技术及 MEMS 传感器 .21.2 MEMS 电容式加速度计检测 ASIC 研究现状及意义 .41.3 本论文的主要研究内容 .7第二章 CMOS 运算放大器的设计 .82.1 CMOS 运放概述 .82.1.1 CMOS 运算放大器设计指标 .92.1.2 CMOS 运算放大器的分类 .112.2 模拟集成电路设计流程 .152.3 本检测电容电路中用到的两级运算放大器设计与实现 .162.3.1 运放结构的选取 .162.3.2 运放性能的仿真 .17第三章 MEMS 电容传感器检测电路系统的设计 .223.1 微电容检测 .223.1.1 微电容检测原理 .223.1.2 微电容检测的常用方法 .223.1.3 本文采用的方法 .293.2 时序电路的设计 .303.2.1 两相不交叠时钟的产生 .313.2.2 二分频电路的设计 .
