基于无源RFID标签的低功耗温度传感器设计

发布时间：2018-01-10 11:21

  本文关键词：基于无源RFID标签的低功耗温度传感器设计　出处：《西安电子科技大学》2016年硕士论文　论文类型：学位论文

  更多相关文章： 无源RFID 温度检测 SAR ADC 低功耗

【摘要】：RFID技术经过几十年的发展,在各个领域得到越加广泛的应用,如交通运输、医疗、商业商品自动化等领域。温度传感器作为传感器中非常重要的一类,通过其元件随温度变化的特性来对温度进行检测,并根据温度不同实现对系统的控制,将温度传感器集成于RFID标签芯片有着非常广泛的应用前景。本文设计了一款应用于无源RFID标签芯片上、可对环境温度精确测量、同时具有低功耗特点的CMOS温度传感器。本文所设计的温度传感器主要包括温度检测模块和温度量化模块。温度检测模块包括感温电路和带隙基准,通过感温元件得到与温度成比例的电压/电流和与温度无关的参考电压。论文对传统CMOS工艺下PNP晶体管和工作在亚阈值区MOS管的温度特性进行分析、对比,得到工作在亚阈值区的MOS管具有更低的功耗。利用工作在亚阈值区MOS管的栅极-源极电压差?VGS与温度成正比的特性,实现感温电路和带隙基准,具有更低功耗的优势;再针对与后级模数转换器ADC的输入范围匹配度,本文专门设计了CTAT(与温度成反比)电路,对感温电路进行改进,将其感温电压的范围从245.7mV提升到709.7mV。论文针对温度检测电路的功耗、精度、以及与后级ADC输入范围匹配度等方面,从系统到模块进行协同改进与折中,设计得到使用的温度检测电路的最终结构。温度量化模块采用低功耗ADC,将温度检测模块得到的感温电压转换为数字信号,对ADC有低功耗、低采样频率、高分辨率的要求。本文设计了一个超低功耗10bits SAR ADC,通过对ADC中的电容阵列DAC及其开关时序进行分析和优化,得到一种新型的低功耗单端开关电容阵列。本文设计的新型单端电容阵列的参考电压VREF为0.5V,仅为传统参考电压的一半,功耗约为传统单端开关的1/8。最终得到10bits SAR ADC的参考电压为0.5V,输入范围为0V~1V,采样频率为10KS/s,SNR为57.66dB,SFDR为72.48dB,SNDR为57.19dB,有效位数ENOB为9.2bit,功耗为0.046μW,达到了设计指标。论文将温度检测模块与温度量化模块整合,得到CMOS温度传感器的总体架构,通过对整体的温度传感器在SMIC 0.18μm CMOS工艺下进行仿真验证,其温度检测的精度达到±0.3℃,总功耗为0.394μW,适用于无源RFID温度检测标签芯片。
[Abstract]:After decades of development, RFID technology has been more and more widely used in various fields, such as transportation, medical treatment, commercial commercial automation and other fields. Temperature sensors as a very important category of sensors. According to the characteristic of the component changing with temperature, the temperature is detected, and the control of the system is realized according to the different temperature. The integration of temperature sensor into RFID tag chip has a wide application prospect. In this paper, we design a passive RFID tag chip, which can accurately measure the environment temperature. At the same time, the CMOS temperature sensor with low power consumption. The temperature sensor designed in this paper mainly includes temperature detection module and temperature quantification module. The temperature detection module includes temperature sensing circuit and bandgap reference. The temperature dependent voltage / current and temperature independent reference voltage are obtained by temperature sensing elements. In this paper, the temperature characteristics of PNP transistors and MOS transistors working in sub-threshold region in traditional CMOS process are divided. Analysis. By contrast, it is found that the MOS transistors operating in the sub-threshold region have lower power consumption. The gate-source voltage difference of the MOS transistors working in the sub-threshold region is used. The characteristic of VGS is proportional to temperature, which realizes the temperature sensing circuit and bandgap reference, and has the advantage of lower power consumption. According to the matching degree of the input range of the ADC, this paper specially designed the circuit of CTAT (inversely proportional to temperature) to improve the temperature sensing circuit. The range of temperature sensing voltage is raised from 245.7 MV to 709.7 MV. The paper aims at the power consumption, precision and matching degree with the input range of ADC. From the system to the module for collaborative improvement and compromise, the final structure of the temperature detection circuit is designed. The temperature quantization module uses low-power ADC. The temperature sensing voltage obtained by the temperature detection module is converted into digital signal, which has low power consumption and low sampling frequency for ADC. In this paper, an ultra-low power 10bits SAR ADCs is designed, and the capacitor array DAC and its switching timing in ADC are analyzed and optimized. A new type of low-power single-ended switched capacitor array is obtained. The reference voltage VREF of the new single-ended capacitor array designed in this paper is 0.5V, which is only half of the traditional reference voltage. The power consumption is about 1 / 8 of that of the traditional single-ended switch. Finally, the reference voltage of 10 bits SAR ADC is 0.5 V, the input range is 0 V / 1 V, and the sampling frequency is 10 KS / s. The SNR is 57.66 dBU SFDR, the SNDR is 57.19 dB, the effective ENOB is 9.2 bit, and the power consumption is 0.046 渭 W. The temperature detection module and the temperature quantification module are integrated to get the overall structure of CMOS temperature sensor. Through the simulation of the whole temperature sensor in SMIC 0.18 渭 m CMOS process, the precision of temperature detection is 卤0.3 鈩，

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