A hybrid power delivery method for asynchronous loads in energy harvesting systems

Energy harvesting is becoming popular for small systems such as micro-sensors or medical implantable devices, which may not need or be able to include large energy storage devices. However power from energy harvesting circuits may be very limited and vary within a large range. Therefore an on-chip intelligent and flexible power delivery method bypassing external energy storage devices and corresponding charging circuits may be advantageous. Also, different computation loads may tolerate different degrees of variance in the supplied VDD. Thus, a hybrid power delivery method fully behaving as switched capacitor dc-dc converter or capacitor bank block to generate stable or variable power supply is developed to cope with variable harvested energy. The method is verified by hardware, which has been employed for VLSI chip testing. It can be considered as a valuable reference for later on-chip fabrication and task & power scheduling research.