LAUSR

With ever-increasing demand of feature-rich portable electronics, single-inductor multiple-output (SIMO) converters are becoming a cost-effective option to provide different supply voltages while maintaining a long battery life. A single-discharge (SDC) control scheme is proposed to simplify the SIMO design, to achieve low cross-regulation, and to support wide range of loads with reasonable power efficiency. A SDC SIMO buck converter with four outputs composed of comparators, phased-locked loop, finite state machine (FSM) controller, and an output stage, is prototyped using TSMC's 0.18-μm BCD process. In addition to the basic switching functions, the FSM controller provides a state skipping feature to allow no-load regulation. Its functionality is verified experimentally and can convert an input voltage from 2.7 to 3.7 V to 1, 1.2, 1.5, and 1.8 V outputs. The simulated peak power conversion efficiency is 86% with a combined output power ranging from 150 to 300 mW. The packaged SDC SIMO converter ICs exhibit a lower measured peak efficiency of 73%, with a cross-regulation of 0.24 mV/mA due to the parasitic bond-wire resistance. The converter prototype can support a wide range of loading conditions, from open circuit to a total output power of 1 W.