电容式湿度传感器读出电路的设计  

Design of the Read-out IC for Capacitor Humidity Sensor

作　　者：肖小霞 魏榕山[1] XIAO Xiao-xia;WEI Rong-shan(College of Physics and Information Engineering, Fuzhou University, Fuzhou 350116, China)

机构地区：[1]福州大学物理与信息工程学院,福建福州350116

出　　处：《中国集成电路》2019年第5期34-38,93,共6页China lntegrated Circuit

基　　金：福建省自然科学基金(2018J01803)

摘　　要：本文提出了一个电容式湿度传感器的读出电路,实现对湿度电容信号到数字信号的转换,即电容数字转换器(CDC)。该CDC采用Sigma-Delta调制技术进行电容信号的转换,同时采用Zoom-i n技术,减少参考电容的大小,扩展电容测量范围。本设计采用SMI C 0. 18μm CMOS工艺,电源电压为1. 8 V,采样时钟频率为250 KHz。仿真结果表明该调制器精度达到13 bi t,整个调制器共消耗电流为180μA,输入电容的共模范围为0-8pF,动态范围为-0. 26 pF～+0. 26 pF。In this paper, a readout circuit of a capacitive humidity sensor is proposed to realize the conversion of the humidity capacitance signal to the digital signal, that is, the capacitance to digital converter (CDC). The CDC uses Sigma-Delta modulation technology to convert capacitive signals, and uses Zoom-in technology to reduce the size of the reference capacitor and expand the capacitance measurement range. This design uses SMIC 0.18μm CMOS process, the power supply voltage is 1.8V, and the sampling clock frequency is 250KHz . The simulation results show that the modulator has an accuracy of 13 bit, the total current consumption of the modulator is 180μA, the common mode measurable range of the input capacitor is 0-8pF, and the dynamic range is -0.26pF^+0.26pF.

关 键 词：电容式湿度传感器 电容数字转换器 SIGMA-DELTA调制 Zoom-in技术 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]