电容式湿度传感器读出电路的设计
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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 1.8 V, and the sampling clock frequency is 250 KHz. 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 0-8 pF, and the dynamic range is-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 1.8 V, and the sampling clock frequency is 250 KHz. 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 0-8 pF, and the dynamic range is-0.26 pF～+0.26 pF.
引文
[1]顾磊. CMOS工艺兼容电容式相对湿度传感器的设计[D].南京:东南大学,2004.
[2] G. C. M. Meijer,Smart Sensor Systems. Chichester,UK:Wiley, 2008.
[3] Nojdelov R, Nihtianov S. Capacitive-Sensor Interface With High Accuracy and Stability[J].IEEE Transactions on Instrumentation&Measurement, 2009,58(5):1633-1639.
[4]刘孟良.全差分电容式传感的CMOS读出电路设计与实现[D].湘潭:湘潭大学,2015.
[5]王阳.基于CMOS工艺的集成微电容式传感器研究[D].合肥:安徽大学,2012.
[6] Tan Z, Chae Y, Daamen R, et al. A 1.2V 8.3nJ energy-efficient CMOS humidity sensor for RFID applications[C]//Vl SI Circuits. IEEE, 2012.
[7] Xia S, Nihtianov S. Power-Efficient High-Speed and High-Resolution Capacitive-Sensor Interface for Subnanometer Displacement Measurements[J]. IEEE Transactions on Instrumentation&Measurement,2012,61(5):1315-1322.
[8] Schreier R, Temes G C. Understanding delta-sigma data converters[M]. New York:IEEE Press/Wiley, 2005.46-80.
[9] Willy Sansen.模拟集成电路设计精粹[M].清华大学出版社, 2007:207-210.
[10] Guo F. Energy-efficient capacitive-sensor interface based on an incremental Delta-Sigma modulator employing current-starved inverter-based OTAs:[Master thesis]. TU Delft, Delft University of Technology, 2011.
[11]池保勇.模拟集成电路与系统[M].北京:清华大学出版社,2009. 332-389.
[12] Pertijs M A P, Huijsing J H. PRECISION TEMPERATURE SENSORS IN CMOS TECHNOLOGY[M].Netherlands:Springer, 2006.
[2] G. C. M. Meijer,Smart Sensor Systems. Chichester,UK:Wiley, 2008.
[3] Nojdelov R, Nihtianov S. Capacitive-Sensor Interface With High Accuracy and Stability[J].IEEE Transactions on Instrumentation&Measurement, 2009,58(5):1633-1639.
[4]刘孟良.全差分电容式传感的CMOS读出电路设计与实现[D].湘潭:湘潭大学,2015.
[5]王阳.基于CMOS工艺的集成微电容式传感器研究[D].合肥:安徽大学,2012.
[6] Tan Z, Chae Y, Daamen R, et al. A 1.2V 8.3nJ energy-efficient CMOS humidity sensor for RFID applications[C]//Vl SI Circuits. IEEE, 2012.
[7] Xia S, Nihtianov S. Power-Efficient High-Speed and High-Resolution Capacitive-Sensor Interface for Subnanometer Displacement Measurements[J]. IEEE Transactions on Instrumentation&Measurement,2012,61(5):1315-1322.
[8] Schreier R, Temes G C. Understanding delta-sigma data converters[M]. New York:IEEE Press/Wiley, 2005.46-80.
[9] Willy Sansen.模拟集成电路设计精粹[M].清华大学出版社, 2007:207-210.
[10] Guo F. Energy-efficient capacitive-sensor interface based on an incremental Delta-Sigma modulator employing current-starved inverter-based OTAs:[Master thesis]. TU Delft, Delft University of Technology, 2011.
[11]池保勇.模拟集成电路与系统[M].北京:清华大学出版社,2009. 332-389.
[12] Pertijs M A P, Huijsing J H. PRECISION TEMPERATURE SENSORS IN CMOS TECHNOLOGY[M].Netherlands:Springer, 2006.