EFFICIENT VOLTAGE REGULATION USING SWITCHED CAPACITOR DC/DC CONVERTER FROM BATTERY AND ENERGY HARVESTING POWER SOURCES

摘要

Recent portable electronic technologies require the power management circuit be efficient, small and cost effective. The switched-capacitor (SC) converter provides a trade-off between the efficiency, the size and the cost that is desirable in many of these new portable technologies. This dissertation investigates different circuit techniques and SC converter topologies to make the SC converters fully adapt to the portable system requirements. To make the SC converter efficient over a wide range of input and output voltages, a family of SC power stages with multiple gain ratio (GR) is developed. Multiple GR allows the converter to provide step-down or step-up voltage conversion while increasing the average efficiency of the converter. These power stages are also capable of providing interleaving regulation that has been proved to be effective in reducing the input and the output noise of the converter. Unlike conventional interleaving, the technique developed in this research uses fewer switches and capacitors. The research also contributes in developing circuit techniques such as charge recycling in the bottom plate parasitic capacitors, local gate driving and adaptive body biasing to reduce the power loss in monolithic SC converter implementation. To control the SC power stage for accurate regulation and fast transient response, a control scheme named adaptive gain/pulse control is developed. The research also investigates the use of multipath compensation scheme in SC converters for ultra fast and low noise performance. The techniques and the topologies developed for SC converters in this research can be effectively implemented in the portable devices to reduce cost, and improve efficiency which leads to longer battery life and circuit implementation using smaller areas.