ABSTRACT A novel low‐power self‐starting energy converter is proposed, which is suitable for triple‐source energy harvesting from the ambient environment. The proposed converter fabricated in 0.18 μm CMOS technology harvests piezoelectric, photovoltaic, and thermoelectric energy with high efficiency, and it is capable of low‐voltage self‐starting without battery power supply. The efficiency of piezoelectric interface is improved by the low‐power active rectifier and the synchronous electric charge extraction technique. The employment of the fractional open circuit voltage maximum power point tracking technique reduces the complexity and the power consumption of the photovoltaic and thermoelectric interfaces. Measured results show that the converter manages three harvesting sources automatically with a minimum quiescent current of 300 nA, and has a peak end‐to‐end efficiency of 47.4% with a die size of 1486 μm × 1439 μm. With respect to other multi‐source energy harvesters, this work specifically displays a series of ultra‐low power design techniques to extremely minimize the intrinsic consumption during operation. The tiny chip size combined with the limited number of required external component, the high end‐to‐end conversion efficiency, and the ultra‐low power consumption make the converter suitable for many critical applications with very limited available power, such as wearable devices or unobserved wireless sensor networks.
Xu et al. (Wed,) studied this question.