Charge Recovery for Energy Harvesting Applications

Energy harvesting systems such as self-powered wireless sensor nodes rely on a diverse set of energy sources in their continuously changing environment for power. A highly flexible power supply with multiple sources is needed to deal with large variation in environmental conditions. This paper describes an integrated power management system for use with multiple energy harvesters, which employs energy awareness and charge recycling. Previous multiple-input power management systems only allow energy to be harvested from a single source at a time [1] (typically the source with the largest voltage) thereby wasting the energy from the other energy harvesters. In order to increase the total energy available, the work presented here allows the system to gather and add together voltages from multiple sources at the same time.