Adaptive Switching Power Converter with Dual-Loop Switched-Capacitor Controller and On-Chip Output Capacitor

An adaptive-output switching converter is proposed. The design uses one-cycle control for fast line regulation and an outer loop for load regulation and fine tuning. The dual-loop operation allows the first integration of output capacitor. A switched-capacitor (SC) integrator is employed in the controller to obtain positive integration with a single-rail power supply, allowing low-cost CMOS fabrication process. To improve the efficiency, a dynamic loss control technique is presented. The circuit was fabricated with 0.35 mum N-well CMOS process. With a supply voltage of 3 V, a voltage ripple of less than 15 mV is measured. The maximum efficiency is 92% with a load power of 475 mW. The converter exhibits a tracking speed of 23.75 mus/V for both start-up and reference voltage transitions. The recovery time for a 20% load change is approximately 9.5 mus