A 76% efficiency boost converter with 220mV self-startup and 2nW quiescent power for high resistance thermo-electric energy harvesting

With the emergence of thin-film thermo-electric generators (TEG), power density and sustainability of energy harvesting sources have improved. These novel power sources however exhibit high internal electrical resistances. Conventional state-of-the-art boost converters encounter low efficiency and potential startup failures when harvesting energy from such sources. This paper presents a highly efficient boost converter for thermo-electric energy harvesting systems based on a novel Power-on-Reset (PoR) driven startup circuit. It utilizes the feedback between TEG, the boost converter, and the PoR circuit, converting a reset signal edge into a train of pulses. The proposed startup circuit is automatically disabled once startup operation is completed, and consumes the quiescent power of 2nW in steady-state. The proposed boost converter has a self-startup TEG voltage of 220mV and a peak power conversion efficiency of 76% with a minimum input for operation being 85mV.