A time-based self-adaptive energy-harvesting MPPT with 5.1-µW power consumption and a wide tracking range of 10-µA to 1-mA

This paper presents a novel ultra-low power maximum power point tracking (MPPT) technique with a wide tracking range. An indirect, non-interrupting and approach using a novel timing-based tracking algorithm is proposed. This reduces processing current consumption down to 3.4-μA. Moreover, the proposed tracking method is self-adaptive to various types of photo-voltaic cells and thermo-electric generators and avoids external re-configuration or change of passive components for different operation conditions. A test chip was fabricated in 65-nm CMOS technology. It can harvest energy within 0.4 V to 1.7 V with a tracking response time of less than 300 ms with the minimum supply voltage of 0.8 V. The tracking efficiency is up to 96.2 % when supplied by a PV micro-cell array using an irradiation range of 200 lux to 1000 lux.