Research Of Power Management ASIC Based On Thermal Energy And Vibration Energy

With the rapid development of Narrow-Band Internet of Things(NB-IoT)in the past two years,it has become an important branch of the Internet of Thing.The wearable device,also known as the Body Sensor Node(BSN),emerged as a carrier for narrowband Internet of Things.It gradually became essential daily necessities for us following the mobile phone.Such devices provide significant advantages in the medical field by continuously monitoring and recording the body's biological signals.In this paper,proposed circuit is designed to use the most direct energy source on the human body—heat energy and vibration energy.Thus,thermocouple generators and piezoelectric vibration energy harvesters are chose as transducers to power a multi-source energyharvested power management ASIC.Focused on the thermoelectric and piezoelectric output characteristics,two kinds of energy harvesters impedance matching circuit is designed to complete the maximum power extraction;then according to their application characteristics,low-power conditioning circuit is designed.The result provides a way for self-powered solutions in the field of wearable devices with good academic and engineering practice.This paper first investigated the market prospects of wearable devices,proposed the necessity of multi-source energy-harvested power management circuit,investigated the research results and development status of multi-source energy harvested chips in recent years,and elaborated the advantages and disadvantages of their respective circuits.Secondly,for the specific application scenarios,the paper analyzed the electrical models of both thermocouple generators and piezoelectric energy harvesters used.Thirdly,according to their output characteristics,corresponding impedance matching circuits are proposed.Due to the characteristics of the thermoelectric ultra-low voltage input,a twostage boost structure,containing an ultra-low-voltage self-startup circuit and a Boost converter,is adopted.As for the piezoelectric vibration energy harvesters,a Buck-Boost converter,which is based on the synchronous electric charge extraction circuit,is used to achieve maximum power extraction.Fourthly,in order to reduce the number of external discrete components,a shared single-inductance multi-source energy compound harvester circuit architecture with a switch array is proposed.It is based on the switch matrix structure of the thermoelectric Boost converter and the piezoelectric synchronous charge extraction circuit.Furthermore,a corresponding low-power conditioning circuit is designed according to different switching cycles of thermocouple generators and piezoelectric vibration energy harvesters,ensuring that the entire power management circuit can be stable,continuous,and efficient.Power supply for the load.Finally,a global layout based on the designed circuit is drew.The design bases on CSMC 0.18?m 5V 1P6 M CMOS EN Process to perform circuit simulation and backend layout drawing.The design of the thermoelectric conditioning circuit output voltage is 3.15 V,and the circuit power consumption is 29?W.Piezoelectric conditioning circ?it with the maxim?m load capacity is 31 mA,and static power consumption is 7.782?W.The simulation results meet the expected requirements,and prove the practicality of the designed power management circuit for multi-source energy harvest.The final circuit uses the thermoelectric module to charge the energy storage capacitor.Meanwhile,the piezoelectric module supplies power to the load.Based on the combined thermal and piezoelectric energy harvester circuit,This not only avoids the slow charging time of the piezoelectric module,but also avoids the disadvantage of low efficiency of start-up circuit when the thermoelectric module working.Through actual investigation,it is possible to complete the power supply for the temperature and humidity sensor and the transmitter module in the wearable device.The proposed circuit,which is used for wearable devices,provides a foundation for the power supply solution of the body sensor nodes.