Research On Key Technologies Of High Efficiency Weak Energy Harvesting In Integrated Circuit

The development of microelectronics technology is changed with each passing day,as well as the development of the mobile communication technologies with high rate,low delay and low power consumption.At the same time,design of chip which possessed low-power and multi-functional has become the research targets.Thanks to the two aspects of research mentioned above,the Internet of Things(Io T)technology has attracted attention,and it has been applied in the automotive industry,smart home,medical electronics and other fields.However,a wider coverage networks and large number of Io T devices supply power with the battery cumbersome.Therefore,in order to solve the questions caused by frequent battery changing,low-power and high-efficiency environmental energy collection technology has been proposed since few years ago.In the energy harvesting,low-power indoor solar energy,human thermal energy and RF energy are considered weak energy.In the paper,a maximum power point tracking(MPPT)with low power DC-DC boost converter is designed for harvest energy.The MPPT can track the maximum power point output of the energy source,so the collection efficiency of the energy collection circuit can be improved efficiently in a complex environment.The high-efficiency DC-DC boost can boost the low-voltage energy to higher voltage for supply load from environmental energy.On the other hand,by analyzing the conduction loss,switching loss and the energy consumption of its own circuit,the optimal frequency of control system is designed to achieve the high efficiency in weak energy harvesting system.The main work and achievements of this paper are included as follows:(1)Low power MPPT was designed.The MPPT is designed with the open-circuit voltage method,which is different from the high-power maximum power tracking circuit and is a suitable method for harvest energy at the microwatt level.By analyzing the effect of leakage current in the sampling voltage and the effect of impedance matching on the maximum power transmission,maximum power tracking of energy source is achieved with the output power of-7d Bm ?-30 d Bm,minimum input voltage of 35 m V,and internal resistance range of 50? ? 10k?.(2)High efficiency converters are studied.The DC-DC boost converter that used zero-current switching(ZCS)is designed to improve conversion efficiency.In the ZCS circuit modules,a high-performance comparator and a timing control circuit is adoped to achieve high efficiency and low power.On the other hand,the driver of the convert is designed with special power supply,it improves the the speed of ZCS and reduces the loss which caused by sub-threshold leakage current.Based on 65 nm CMOS process,the DC-DC boost converter is designed with weak energy maximum power tracking.By using Cadence,the simulations results is shown as follows: When the boost converter of the energy source output power varied from-7d Bm ?-30 d Bm,the output voltage of the DC-DC converter is 1000 m V,the peak conversion efficiency is 90.4%,and the peak tracking efficiency is 99.8%.At the same time,and total power of the convert is less than 1.2?W.