Single-inductor 4-Output DC/DC Buck Converter with Comparator-based Fixed-frequency Single-discharge Control

With ever increasing demand of portable electronics, Single-Inductor Multiple-Output (SIMO) converters are becoming a popular option to design DC/DC converters to reduce cost and maintain long battery life. Single-discharge (SDC) control scheme is proposed to simplify the SIMO design, achieve low cross-regulation, and to support wide range of loads. The proposed converter with 4 outputs is prototyped using TSMC 0.18 Âľm BCD Gen II process. The chip is tested for its functionality, capable of converting 2.7 to 3.7 V input to 1, 1.2, 1.5, and 1.8 V outputs. The load regulation and efficiency performance of the converter is less than expected due to the unforeseen layout and bond wire parasitics. The peak efficiency of the converter is 73.2%, with the cross regulation of 0.143 mV/mA. The converter prototype is able to support wide range of loads, from disconnected loads to total output power of 1W.M.A.S