A 94.2% Peak Efficiency Full Duty Range Flying-Capacitor Sharing Dynamic Four-Path Hybrid Converter With Reduced Body Diode Loss Technique

This paper proposes a flying-capacitor sharing dynamic four-path (FCSD-4P) hybrid converter, designed to achieve a duty cycle (D) ranging from 0% to 100%, addressing the conventional limitation of D <50% and enabling a wide voltage conversion ratio (VCR) from 0% to 50%. The FCSD-4P dynamically adjusts the number of energy pathways in real-time to maintain high efficiency across a wide range of load currents and employs discontinuous conduction mode (DCM) during light load conditions to improve light-load efficiency. Utilizing only low-voltage (LV) devices, the FCSD-4P hybrid converter effectively minimizes area consumption and conduction losses. The design also integrates a high-accuracy linear current sensor, fast transient mode, a successive-approximation register (SAR) based zero current detector (ZCD), and reduced body diode loss (RBDL) techniques, enhancing transient response and reducing energy loss in DCM. Fabricated using a 150nm BCD process, the converter occupies a chip area of $3860\times 2100~\mu $ m2. In a 6V to 1.8V conversion, the converter achieves a peak efficiency of 94.2%.