Design Of Energy Collection Power Management Chip With Low Self Starting Voltage

The Internet of Things has become one of the most promising hot spots in the current semiconductor industry,and its popularity has put forward new requirements on the performance of existing electronic products in terms of power consumption and usage environment.With the reduction of chip process size,the power consumption of electronic products is getting lower and lower,thus extending the battery life,but self-powering by harvesting energy from the environment is still necessary because it eliminates the hard need of batteries and makes the autonomous operation of electronic systems possible.Micro-wattage power extracted from human heat using thermoelectric generators(TEGs)can achieve the power autonomy we need,but there are certain technical difficulties due to their low output voltage.How to solve these technical difficulties has become an important research element in the design of current energy harvesting systems.In this paper,an energy harvesting power management circuit with low self-starting voltage is designed for thermoelectric energy harvesting applications.In order to realize the normal operation of the system without battery,the designed circuit adopts a two-stage step-by-step self-start structure to realize the self-start function at low input voltage.In order to extract the maximum energy from the TEG under a smaller temperature gradient,the designed circuit integrates a maximum power point tracking(MPPT)module to achieve on-chip MPPT,and solves the problem of clock frequency variation with supply voltage by means of reference voltage trimming to improve the overall stability of the system.In order to improve the energy conversion efficiency,this design also contains the over-zero detection(ZCS)module,which detects the position of zero current during the discharge of the inductor and ends the discharge process in time by using two comparator monitoring,greatly reducing the energy backflow at the load side.Also,in order to solve the unstable output voltage of the Boost converter when the ambient energy changes,this design also integrates a digital low dropout linear regulator(D-LDO)module at the output side to generate a stable output voltage.The circuit designed in this paper is implemented in TSMC 0.18μm process,with a minimum self-start voltage of 180 m V and a minimum operating voltage of 10 m V.the average power consumption of the Boost converter under normal operation is 24.6μW,the output voltage range is 1.4-1.7V,and the end-to-end conversion efficiency of the Boost converter is 78.33% at the TEG open circuit voltage of 100 m V.The output stage D-LDO stabilizes the output voltage at 1.2V with a dynamic power consumption of 27.5μW.