A Two-Stage 12–1-V Converter Featuring Regulated Resonant SC Regulators and Collaborative Control Scheme Shengdao Ren, Student Member , IEEE, Yukan Du, Student Member , IEEE

Abstract

In the field of power converters for data centers, the two-stage architecture has received widespread attentions due to its various advantages. Especially, the switched-capacitor voltage regulator (SCVR) becomes popular as the second-stage converter owing to its high efficiency and power density. However, the SCVR su ffers from poor voltage regulation and limited load capacity. To address these limitations, this article presents a two- stage converter featuring a regulated resonant switched-capacitor (ReSC) second-stage design. Thanks to the resonant operation of the ReSC, the converter achieves the superior power density and load capacity using a compact sub-nano-henry trace inductor. In addition, the resonant operation paves way for the voltage regulation, which is further employed for enhancing transient performances. Finally, to overcome the inherent e fficiency versus voltage regulation tradeo ff for the ReSC, a collaborative control scheme is built between the first and second stages, which adaptively adjusts the intermediate bus voltage to maintain the ReSC always in the e fficient non-regulation mode for the entire output voltage range, leading to a high e fficiency for a wide voltage and current range. By employing discrete GaNFETs for the first stage and 65-nm CMOS technology for the ReSC and controller design, the proposed two-stage converter achieves a measured system peak e fficiency of 89.3% for 12:1-V conversion. With a 4-A /20-ns load current step, the measured undershoot vo