Design Of A High Efficiency P-SSHI Rectifier Circuit For Vibration Energy Harvesters

With the development of Internet of Things technology,low power sensor networks has been widely used in various fields.Using micro-energy harvesting technology instead of traditional batteries to supply power for the Internet of Things system can not only protect the environment,but also extend battery life.In recent years,micro-energy harvesting technology has been paid attention by researchers.Vibration energy harvesting is a hot research topic,and the demand for the design of power management circuit for vibration energy harvester is also increasing gradually.However,due to the inductive component characteristics of the vibration energy harvester,there is a phase difference between the voltage and the current,which leads to the large loss of charge,resulting in low conversion efficiency.In order to improve the conversion efficiency,the industry has studied a variety of rectifier circuit structures for vibration energy harvesting.Among them,current research frontiers in the world are related methods of collecting charges in phase difference time series process by using switch-controlled inductors.Based on the structure of Parallel Synchronized Switch Harvesting Inductor(P-SSHI),this paper introduces a high-efficiency vibration energy acquisition power management circuit chip design ideas and methods.According to the design requirements of the harvester,this paper designs a switching structure based on P-SSHI to control the charging and discharging of inductance,and designs a control signal generation circuit for it,which collects and transfers the phase-difference charge which the full bridge rectifier circuit should be lost to the energy storage capacitor.In order to further improve the conversion efficiency,this paper also designs the optimal efficiency point tracking module(opt)and high precision current reference module with power supply rejection ratio of 62 db.According to the harmonic balance theory,the working voltage is stabilized at the optimal value.In the whole design,all circuit modules realize the self-power supply of the system,which reduces the dependence on external circuits and standby power supply.In this paper,common-gate comparator,cascode comparator and hysteresis comparator are used instead of traditional comparator to improve circuit performance and reduce the power consumption of control logic.The folded-cascode structure is also applied to the current reference,and the high-precision current reference with high PSRR is obtained.It has certain reference value for other energy acquisition circuits.The working current of the circuit is only 500 nA.Based on Silterra 0.18 um standard 5V CMOS process,this paper designs vibration energy harvesting rectifier circuit based on P-SSHI and completes layout design and post-simulation.The core circuit area is 0.168 square millimeters.According to the simulation results,when the input signal frequency is 50 Hz and the internal supply voltage is 3.4V,the peak conversion efficiency of the system is 83.2%(80.3% in post-simulation).Compared with the results of other references,the rectifier circuit designed in this paper has higher conversion efficiency when it meets the design requirements.