A Novel Power Delivery Method for Asynchronous Loads in Energy Harvesting Systems

DC/DC conversion has been an integral part of the power delivery chain in energy harvesting systems because the conventionally targeted synchronous computation load demands stable Vdd, which cannot in general be supplied by power harvesters directly. However, asynchronous computation loads, in addition to their potential power-saving capabilities, can be made tolerant to a much wider range of Vdd variance. This may open up opportunities for much more energy efficient methods of power delivery to be adopted. This paper presents in-depth investigations into the behavior and performance of different power delivery methods driving both asynchronous and synchronous load for the first time. A novel power delivery method, which employs a capacitor bank for adaptively storing the energy from power harvesters depending on load and source conditions, is developed. Its advantages, especially when driving asynchronous loads, are demonstrated through comprehensive comparative analysis.