Design Of A CMOS Fully-Integrated Nano-Power Micro Energy Harvesting Circuit

With the rapid development of the Internet of Things,the micro energy harvesting technology used as a replacement of conventional batteries has gradually become a hot topic at home and abroad.Based on the SMIC 0.18 ?m CMOS process,two different energy harvesting circuits for vibrational energy and multi-source energy have been designed in this thesis respectively.By adopting nano-power design techniques,achieving performance optimization and structural innovation on traditional circuits,both circuits get better performance,which makes them more suitable for environmental micro energy acquisition and power management.The piezoelectric vibrational energy harvesting circuit presented in this thesis mainly includes a rectifier circuit,a peak detection circuit,a zero voltage detection circuit,a zero current detection circuit,a current reference circuit,a LDO circuit,an asynchronous logic control circuit and a backup converter.The low-power current reference circuit provides higher-precision reference current and voltage;The high-stability LDO circuit offers external sensors a stable power supply;The asynchronous logic control circuit reasonably arranges each energy extraction process;The backup converter improves circuitry environmental adaptability and vibrational energy utilization.Simulation results show that as low as 111 nA quiescent current in all is consumed and a peak energy conversion efficiency of 89.4% is achieved.Moreover,this circuit is characterized by small size,high integration,strong environmental adaptability and fully autonomous operation.Based on the above-mentioned circuit,a nano-power self-sufficient multi-source energy harvesting circuit for solar,thermal,and vibrational energy is designed.This circuit mostly contains three different interface circuits respectively used for piezoelectric vibrational energy,low-light energy,and thermal energy,a Buck-Boost converter,a zero current detection circuit,a priority control circuit and an oscillation cancellation circuit.In the interface circuit of piezoelectric vibrational energy,a low-power active rectifier is employed to improve vibrational energy extraction efficiency and a passive self-starting circuit makes the system automatically perform a battery-less start-up from a fully discharged state.In the interface circuit of low-light energy or thermal energy,a FOCV MPPT circuit is applied to track the maximum output power of thermoelectric or photoelectric converter.In addition,a priority control circuit enables the whole system to extract the energy from each input source efficiently and orderly.Simulation results show that the quiescent current can be down to 100nA;The peak efficiency for single source is up to83.6% and 71.5% during multi-source operation.Measurement results show that the chip can enable the system self-starting and store input energy into the output capacitor CDD with the help of the control circuit to realize the chip self-powered.