Study And Design Of Energy Harvesting Power Management Chip For Wireless Sensor Networks Nodes

With the rapid development of the Internet of Things and the widespread usage of wearable devices,sensors of wireless sensor network nodes(WSNs),as well as the implantable and wearable electronic devices present a very urgent need for energy supply.Therefore,harvesting and store techniques of weak energy has attracted the attention of researchers since they can be utilized to reduce or eliminate the dependence on batteries.Among them,a new generation of power management ICs,ranging from microwatts(?W)to milliwatt(mW),that can efficiently extract and manage power sources from light,heat or mechanical energy sources,is manifested to be significant.This thesis focuses on the energy demand for wireless sensor network nodes,to study and design light energy harvesting power management chips.The main work is listed as follows:(1)The continuous control mode of the system is proposed.A control mode,which is capable of stably operating in the MPPT and responding to transient changes of a wide range of load quickly,is realized by Matlab theoretical simulation verification and circuit design,whose maximum load response is 300 m A.(2)A novel full-wave current sensor circuit with fast response is proposed by introducing an improved Gm-Boosting OP AMP and the output structure of mirrored current source suppression.Hence,the entire sampling circuit has satisfactory performance,in which the sampling accuracy is higher than 93% and the response time is less than 8ns when the inductor current ranges from 100 mA to 2.1A.(3)High-sensitivity and low-power DCM detection method is adopted.By introducing a clock sampling comparator,DCM detection can be quickly responded,avoiding the drawbacks of high power consumption,long delay and low sensitivity that exists in the traditional DCM detection.Based on the above-mentioned design features,the design scheme of the energy harvesting power management chip for wireless sensor network nodes is realized.The proposed system is designed and verified by a 0.18?m HV(high voltage)CMOS process,It is demonstrated that the designed power management chip system can acheived: MPPT tracking,automatic buck-boost,stable operation in the COT,DCM or CCM mode based on changes in load and input source and efficient energy conversion control whose efficiency reaches 89% when the input power is 34 mW.It is capable of rapidly responding to load changes,with response time of less than 35?s.Furthermore,a wide range of energy input and load changes can be achieved,with input voltage range of 0.5V~5V,output voltage range of 1V-5V,with load capacity of 300mA.