A Single-Inductor Multiple-Output DC–DC Converter With Fixed-Frequency Victim-Last Charge Control for Reduced Cross Regulation
Yang Li, Mo Huang, Rui P. Martins, Yan Lü
Abstract
This paper presents a single-inductor multiple-output (SIMO) DC-DC converter with fixed-frequency victim-last charge control. This scheme switches the load-transient channel (victim) to the last of the charging sequence, addressing the inherent cross-regulation issue in conventional charge control SIMO. We first analyze why the conventional fixed-frequency charge control has such an issue. Then, we present the working principle of the proposed scheme. After that, we propose a charge-error calibration technique that minimizes the side effects caused by victim-last control, ensuring a smooth order switching of the original last channel. We implemented and fabricated the proposed SIMO DC-DC converter in a 0.18-<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>m BCD process. Measurement results show that we are able to reduce the cross-regulation to 0.057mV/mA with a 225-mA load step under fixed switching frequency. The measured peak efficiency is 84.1%.