Abstract—The potential application space for miniaturized systems like wireless microsensors is expansive, from reconnaissance mission work and remote sensors to biomedical implants and disposable consumer products. Conforming to microscale dimensions, however, constrains energy and power to such an extent that sustaining critical power-hungry functions like wireless communication is next to impossible. Harvesting ambient energy offers an appealing alternative, except the act of transferring energy requires power that could easily exceed what the transducer generates in the first place. This paper discusses how to design low-power switched-inductor converters capable of producing net energy gains when supplied from lowpower piezoelectric and electrostatic kinetic-harvesting sources. I. HARVESTING KINETIC ENERGY IN VIBRATIONS Wireless microsensors can enjoy popularity in, for example,

The PicoCube is a 1cm 3 sensor node using harvested energy as its source of power. Operating at an average of only 6uW for a tirepressure application, the PicoCube represents a modular and integrated approach to the design of nodes for wireless sensor networks. It combines advanced ultra-low power circuit techniques with system-level power management. A simple packaging approach allows the modules comprising the node to fit into 1 cm 3 in a reliable fashion.