Research On Low-power Wake-up Circuit Applied To IoT Node Chip

In recent years,Internet of Things technologies such as wireless sensor networks and body area networks have developed rapidly and have been widely used in medical,education,military,smart cities and other fields.However,limited energy supply is the main problem faced by this type of technology.The research and design of node chips with high integration,low power consumption,high performance,miniaturization,low cost,and long lifetime has always been a research hotspot in academia and industry.This thesis conducts in-depth research on low-power wake-up circuits used in Io T node chips.The main work and research results of this paper include:1.This paper first introduces and analyzes the working modes of two wake-up circuits(radio wake-up and timing wake-up),and then focuses on the analysis of oscillator circuit in the timing wake-up,including oscillator technical indicators and analysis of different oscillator circuits.Afterwards,a theoretical analysis of the commonly used wake-up receiver architecture is carried out.This laid the foundation for the subsequent design of the relaxation oscillator and wake-up receiver.2.A low power trimming-free CMOS relaxation oscillator with process and temperature compensation is proposed.Firstly,the traditional relaxation oscillator architecture is analyzed,then focusing on the factors that affect frequency accuracy and stability.Aiming at the problems of the delay and offset voltage of the comparator,a low power trimming-free CMOS relaxation oscillator with process and temperature compensation is proposed.In this circuit,the transistors of the two current sources work in the sub-threshold region and the saturation region respectively.This design compensates for the instability of the RC time constant with temperature and process variation.In addition,the oscillation period of the circuit is determined by the ratio of three resistors of the same type,which offsets the influence of the process and temperature variation on the resistance value.At the same time,it can also solve the problem of deterioration of the temperature compensation effect under extreme temperature.3.A wake-up receiver chip using direct detection is designed.The chip mainly includes circuit modules such as envelope detector,baseband amplifier,comparator,reference voltage source,reference current source and so on.This paper discusses the circuit structure,working principle and circuit simulation of each module in detail,and focuses on the analysis of passive envelope detector,two-stage baseband amplifier and hysteresis comparator.In addition,this paper gives the simulation results of each circuit module under different condition.Finally,the thesis gives the overall circuit simulation and layout design of the wake-up receiver.4.Both the relaxation oscillator and the wake-up receiver are designed with 0.18?m CMOS technology.After completing the layout design and extracting the parasitic parameters through,the post-simulation shows that the working voltage of relaxation oscillator is 1.2 V,the working frequency is 22 KHz,the frequency error is less than ±3.5%,and the power consumption is 358 n W.The working frequency of the wake-up receiver is 433 MHz,and the data frequency is 10 KHz.After post-simulation,the receiver sensitivity is-50 d Bm,and the power consumption is 3.4?W.