Energy harvesting integrated circuits are the key component for the next generation wireless sensor node and wearable electronic devices as they can harvest energy from the surrounded environment and convert to electrical energy to supply power for the entire system. This self-sustained functionality makes eliminating the wired connection between an electric socket and a sensor node possible. In the upcoming internet of things (IoTs) and 5G generation, applications with equipped energy harvesting system are drawing more and more attention.

The output voltage produced by an energy harvester is very small and requires a boost converter to boost up the voltage for storage or directly use. As the technology keeps scaling down, application required below 0.5-V supply becomes more demanding....[ Read more ]

Energy harvesting integrated circuits are the key component for the next generation wireless sensor node and wearable electronic devices as they can harvest energy from the surrounded environment and convert to electrical energy to supply power for the entire system. This self-sustained functionality makes eliminating the wired connection between an electric socket and a sensor node possible. In the upcoming internet of things (IoTs) and 5G generation, applications with equipped energy harvesting system are drawing more and more attention.

The output voltage produced by an energy harvester is very small and requires a boost converter to boost up the voltage for storage or directly use. As the technology keeps scaling down, application required below 0.5-V supply becomes more demanding. Hence, subthreshold operated circuit with low power consumption for such applications is desired.

To achieve this goal, a boost converter with ultralow-voltage time-domain control for thermoelectric generators (TEG) is proposed in this thesis. A subthreshold 0.3-V voltage supplied control system is constructed using time-domain and constant-on time (COT) approach. The maximum power point tracking (MPPT) is realized using fractional open-circuit voltage (FOCV) scheme. A 0.3-V ultralow output voltage is achieved with this single boost converter. The proposed converter is implemented in UMC 0.13-μm standard CMOS process. The measured minimum TEG open circuit voltage which can maintain harvesting is 80 mV. The power consumption of the control circuit is down to 840 nW. The peak end-to-end efficiency is 72.1% at 170-mV open circuit voltage where the input power is 34.4 μW. The chip area is 1.46 mm × 0.8 mm including all input and output pads.