An Energy Combiner for a Multi-Input Energy-Harvesting System

An energy combiner for delivering electrical energy harvested simultaneously from individual energy harvesters (EHs) to a single energy storage device such as a battery is presented. It is designed as a modular architecture to be handled as a subsystem and supports an arbitrary number of EHs, which can be connected to the energy combiner in a hot-pluggable form. With the adaptive connection flows of a novel control algorithm, the energy harvested from each EH can be transmitted to an energy storage device without interfering with each other. An evaluation system is implemented, including the energy combiner circuit fabricated in a $0.13\mbox{-}\mu\mbox{m}$ CMOS process. The experimental results show that the energy combiner, with a low power consumption of $1.55\ \mu\mbox{W}$ , achieves a maximum energy-combining efficiency of up to 95% for three input sources.