A 43%@0.1V efficiency self-sustaining solar energy harvester in indoor lighting

This paper presents a self-sustaining solar energy harvester (EH) based on 130nm process, which consists of a low voltage cold start (CS) circuit and a high efficiency boost charger. The CS circuit makes the boost charger self-sustaining and start the boost circuit from the 100mV input. An adaptive switch frequency modulation (SFM) and switch capacitor modulation (SCM) are proposed to minimize the switch loss and conduction loss of boost charger, thus reduce overall circuit power consumption. The proposed boost charger utilizes a dual voltage technique for reducing the power dissipation of the internal circuit. The efficiency of the boost charger ranges from 43% at V_IN = 100mV to 65% at V_IN = 300mV.