【作者】 刘旭；

【导师】 曹伽牧；

【作者基本信息】 哈尔滨工业大学 ， 集成电路工程（专业学位）， 2023， 硕士

【摘要】 快速信息化的21世纪需要大量准确的气体传感器信息支撑人们对日常生活、科研过程、工程生产过程安全的高要求,金属氧化物气体传感器以其简单的结构、迅速缩小的体积和广泛的气体测量种类赢得了人们的青睐。为实现精确的金属氧化物气敏元件信号测量,气敏元件特性将影响着对应接口电路的结构和指标。基于ADC结构的分压法传感信号测量方式中,ADC设计复杂、面积大且没有全面考虑金属氧化物气敏元件本身的半导体、电容特性,为更合理的搭配金属氧化物气敏元件,本文采用了电阻频率转换电路作为金属氧化物气敏元件的接口电路,共同组成可实用的可靠气体传感器。本文从理论模型和元件结构两方面详细阐述了目前以SnO₂为主的金属氧化物气敏元件的敏感机理,利用商用气敏元件详细分析了元件固有的半导体特性和电容特性,指出目前气敏元件接口电路设计要求,明确了电阻频率转换电路完全符合金属氧化物气敏元件接口电路的要求。针对电阻频率转换电路进行了详细的研究,阐明了阻频率转换电路的基本原理,针对电路内各个模块进行了精度影响因素分析论述,形成了电路电阻电流转换模块、电流电压转换模块以及电压频率转换设计方案。基于韩国东部HiTek 180nm CMOS工艺实现了整体电路设计,电路工作在1.8V低压电源电压下,版图设计结构通过drc和lvs验证,版图设计结果表明电路整体芯片面积为775.48μm×533.14μm,后仿结果表明电路可测量输入气敏元件电阻范围为2kΩ～1GΩ,在在3.2kΩ以上保持线性误差小于5%,动态范围约为134.3d B,最大功耗为2.142m W,满足设计要求。更多还原

【Abstract】 The rapidly informing 21st century requires a large amount of accurate gas sensor information to support the high demand for safety in daily life,research processes,and engineering production processes.Metal oxide gas sensors have won popularity for their simple structure,rapidly shrinking size,and wide range of gas measurement types.In order to achieve accurate metal oxide gas sensor signal measurement,the sensing element characteristics will influence the structure and index of the corresponding interface circuit.In the ADC-based structure,the ADC design is complex,large in area,and does not fully consider the semiconductor and capacitive characteristics of the metal oxide sensing element itself.In order to more reasonably match the metal oxide sensing element,this paper adopts a resistive frequency conversion circuit as the interface circuit of the metal oxide gas sensing element,which together form a practical and reliable gas sensor.In this paper,the sensitive mechanism of metal oxide gas sensor mainly SnO₂ is described in detail from two aspects of theoretical model and component structure,and the inherent semiconductor and capacitance characteristics of the component are analyzed in detail by using the commercial gas sensor,and the design requirements of the interface circuit of the sensor element are pointed out.It is clear that the resistance frequency conversion circuit meets the requirement of metal oxide gas sensor interface circuit.In this paper,the resistance frequency conversion circuit is studied in detail,and the basic principle of the resistance frequency conversion circuit is expounded.The influencing factors of precision are analyzed and discussed for each module in the circuit,and the circuit resistance current conversion module,current voltage conversion module and voltage frequency conversion design scheme are formed.The overall circuit design was realized based on Hi Tek 180nm CMOS technology.The circuit worked at 1.8V low voltage supply voltage.The layout design structure was verified by drc and lvs.The layout design results showed that the overall chip area of the circuit was 775.48μm×533.14μm.The linear error is less than 5%above 3.2kΩ,the dynamic range is about 134.3d B,and the maximum power consumption is 2.142m W,which meets the design requirements.更多还原