超高频RFID标签低功耗时钟电路的设计与实现
发布时间：2018-10-22 16:30
【摘要】：随着国家物联网战略的推行,智能汽车、智能家居等新概念也相继被提出。作为一种发展趋势,物联网给了我们很大的想象空间。物联网的发展离不开射频识别技术(Radio Frequency Identification,RFID)——一种利用射频信号空间耦合实现非接触式信息传递的技术。无源UHF RFID标签正是运用了这种技术,才发挥出其识别距离远,准确性高,同时可识别多个目标等受市场青睐的特点。无源UHF RFID标签芯片模拟前端和数字基带能否良好的连接是非常关键的,因此,作为标签芯片内连接二者的“桥”——时钟电路就显得尤为重要。本文主要针对UHF RFID标签芯片的功能需求,提出三种时钟电路的设计,即环形振荡器(Ring Oscillator)和弛豫振荡器(Relaxation Oscillator)及改进版驰豫振荡器,通过严格的公式推导,并对电路中所有细节做出了具体分析,深入研究了三种电路结构及工作原理,最后都给出相应的仿真结果,验证电路的功能和性能。首先设计出一款新型的环形振荡器,公式推导出频率的表达式,从振荡器频率表达式可以看出,时钟频率的稳定对工作电压和电流的要求很高。其电路结构主要包括:核心电路三级环形振荡器,通过寄生电容的充放电形成正弦信号,并保持稳定;电平转换电路,提高由环形振荡器产生的信号幅度;二分频电路,调节信号的占空比,是频率稳定。在其前端的基准电路中加入一个校准电路,可对频率进行校准,改善因工艺引起的偏差。设计一个简单的弛豫振荡器,在实现该电路功能的前提下,对电路进行具分析,为之后新版本打下基础。该驰豫振荡器结构简单,且在功能和性能上也有可取之处,例如温度抑制能力和功耗方面都优于环形振荡器。通过公式推导,可以知道,当电容两端的电压和基准电流之比为常数时,频率跟基准电流无关。改进版驰豫振荡器是针对上一版本做出的改进的一款电路,通过提高电路对电源电压、基准电流和温度的抑制能力来改善电路。本文设计了七位电阻比例自校准电路,通过数字部分的逻辑运算,可以准确校准时钟频率,确保时钟校准精度要求的同时,克服了由于工艺的原因造成时钟的偏差。这样最终设计出电流电压温度抑制能力强、频率精度高、偏差小的弛豫振荡器,满足了UHF RFID芯片系统的要求。
[Abstract]:With the implementation of the national Internet of things strategy, smart cars, smart home and other new concepts have been put forward. As a development trend, the Internet of things gives us a lot of imagination. The development of the Internet of things can not be separated from the RFID (Radio Frequency Identification,RFID), a technology to realize the non-contact information transmission by using the spatial coupling of radio frequency signals. With this technique, passive UHF RFID tags have the advantages of long recognition distance, high accuracy and recognition of multiple targets. Whether the analog front end and digital baseband of passive UHF RFID tag chip can be well connected is very important. Therefore, as the "bridge" of the tag chip connecting them, the clock circuit is very important. Aiming at the functional requirement of UHF RFID tag chip, this paper presents three kinds of clock circuits: ring oscillator (Ring Oscillator), relaxation oscillator (Relaxation Oscillator) and improved relaxation oscillator. All the details of the circuit are analyzed in detail, and three kinds of circuit structure and working principle are deeply studied. Finally, the corresponding simulation results are given to verify the function and performance of the circuit. First, a new type of ring oscillator is designed, and the expression of frequency is deduced. From the expression of frequency of oscillator, it can be seen that the stability of clock frequency requires high working voltage and current. Its circuit structure mainly includes: core circuit three-stage ring oscillator, through parasitic capacitance charge and discharge to form sinusoidal signal, and maintain stability; level conversion circuit, improve the signal amplitude produced by ring oscillator; two frequency division circuit, Adjust the duty cycle of the signal, the frequency is stable. A calibration circuit is added to the reference circuit of the front end, which can calibrate the frequency and improve the deviation caused by the process. A simple relaxation oscillator is designed, and the circuit is analyzed on the premise of realizing the function of the circuit, which lays the foundation for the new version. The relaxation oscillator is simple in structure and has some advantages in function and performance, such as temperature suppression ability and power consumption. By formula derivation, we can know that when the ratio of voltage to reference current at both ends of capacitor is constant, the frequency is independent of reference current. The improved relaxation oscillator is an improved circuit for the previous version, which improves the circuit by improving its ability to suppress the supply voltage, reference current and temperature. In this paper, a seven-bit resistor proportional self-calibration circuit is designed. Through the logic operation of the digital part, the clock frequency can be accurately calibrated, and the clock calibration accuracy can be ensured, and the clock deviation caused by the process can be overcome at the same time. Finally, a relaxation oscillator with strong current voltage temperature suppression ability, high frequency precision and small deviation is designed, which meets the requirements of UHF RFID chip system.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN402;TP391.44
本文编号：2287692
[Abstract]:With the implementation of the national Internet of things strategy, smart cars, smart home and other new concepts have been put forward. As a development trend, the Internet of things gives us a lot of imagination. The development of the Internet of things can not be separated from the RFID (Radio Frequency Identification,RFID), a technology to realize the non-contact information transmission by using the spatial coupling of radio frequency signals. With this technique, passive UHF RFID tags have the advantages of long recognition distance, high accuracy and recognition of multiple targets. Whether the analog front end and digital baseband of passive UHF RFID tag chip can be well connected is very important. Therefore, as the "bridge" of the tag chip connecting them, the clock circuit is very important. Aiming at the functional requirement of UHF RFID tag chip, this paper presents three kinds of clock circuits: ring oscillator (Ring Oscillator), relaxation oscillator (Relaxation Oscillator) and improved relaxation oscillator. All the details of the circuit are analyzed in detail, and three kinds of circuit structure and working principle are deeply studied. Finally, the corresponding simulation results are given to verify the function and performance of the circuit. First, a new type of ring oscillator is designed, and the expression of frequency is deduced. From the expression of frequency of oscillator, it can be seen that the stability of clock frequency requires high working voltage and current. Its circuit structure mainly includes: core circuit three-stage ring oscillator, through parasitic capacitance charge and discharge to form sinusoidal signal, and maintain stability; level conversion circuit, improve the signal amplitude produced by ring oscillator; two frequency division circuit, Adjust the duty cycle of the signal, the frequency is stable. A calibration circuit is added to the reference circuit of the front end, which can calibrate the frequency and improve the deviation caused by the process. A simple relaxation oscillator is designed, and the circuit is analyzed on the premise of realizing the function of the circuit, which lays the foundation for the new version. The relaxation oscillator is simple in structure and has some advantages in function and performance, such as temperature suppression ability and power consumption. By formula derivation, we can know that when the ratio of voltage to reference current at both ends of capacitor is constant, the frequency is independent of reference current. The improved relaxation oscillator is an improved circuit for the previous version, which improves the circuit by improving its ability to suppress the supply voltage, reference current and temperature. In this paper, a seven-bit resistor proportional self-calibration circuit is designed. Through the logic operation of the digital part, the clock frequency can be accurately calibrated, and the clock calibration accuracy can be ensured, and the clock deviation caused by the process can be overcome at the same time. Finally, a relaxation oscillator with strong current voltage temperature suppression ability, high frequency precision and small deviation is designed, which meets the requirements of UHF RFID chip system.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN402;TP391.44
【参考文献】
相关期刊论文 前1条
1 陈莹梅,王志功,朱恩,冯军,章丽,熊明珍;一种高工作频率、低相位噪声的CMOS环形振荡器[J];光电子·激光;2004年10期
，本文编号：2287692
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