We propose an energy-harvesting management unit to interface a PV harvester with a storage supercapacitor while generating a 1V regulated supply VREG. Direct connection between stacked PV cells and VREG allows virtual 100% conversion efficiency between the harvester and the supplied circuits, while the use of a single bidirectional switched capacitor DC/DC converter between VREG and the supercap allows 0.48mm2 area in a 65nm IoT vision SoC with a single external filtering capacitor. To cope with the 0-3V charge dependent supercap voltage range and the wide 5μW-10mW harvester/load power range, the converter features adaptive selection between multiple voltage gains and power modes.
['David Bol', 'El Hafed Boufouss', 'Denis Flandre', 'Julien De Vos']
A 0.48mm 2 5μW-10mW indoor/outdoor PV energy-harvesting management unit in a 65nm SoC based on a single bidirectional multi-gain/multi-mode switched-cap converter with supercap storage