Single-Inductor Quad-Output Switching Converter With Priority-Scheduled Program for Fast Transient Response and Unlimited Load Range in 40 nm CMOS Technology Wei-Chung Chen, Student Member , IEEE, Yi-Ping Su, Tzu-Chi Huang, Tsu-Wei Tsai, Ruei-Hong Peng, Kuei-Liang Lin

Abstract

System-on-a-chip (SoC) applications require multiple power supply voltages with the features of low no ise for analog cir- cuits and high efficiency for digital circuits. Thus, this paper pro- poses the priority-scheduled program (PSP) for the single-inductor quad-output (SIQO) switching converter . This technique manages energy delivery to multiple outputs, facilitates fast transient re- sponse, and reduces cross-regulati on simultaneously. Moreover , a level bypass detector (LBD) is used to o vercome the limitation of significant loading differences among quad outputs in conventional designs because the PSP techniqu e cantransfer additional energy to low-priority outputs to avoid ove rshoot voltage at high-priority outputs. Furthermore, voltage disturbance can be filtered out using two additional low-dropout regulators that operate as buffers cas- caded at two low-priority outpu ts. Therefore, the SIQO converter that is fabricated in 40 nm CMOS technology satisfies the power requirements in portable electronics given its low cross-regulation of 0.2%, fast transient respo nse of 15 s, and an output voltage ripple that is smaller than 30 mV.