An Auto-Reconfigurable AC-DC Regulator for Wirelessly Powered Biomedical Implants With 28% Link Efficiency Enhancement

摘要

This brief presents an auto-reconfigurable load-dependable ac-dc regulator for wirelessly powered biomedical implants. In wireless power transmission, the peak link efficiency that typically limits the overall system efficiency only occurs at a certain nominal load for a given link design. The proposed reconfigurable ac-dc regulator can automatically switch between doubler and quadrupler rectifier topologies to provide dynamic input impedance matching to the link as the average load current of the regulator varies during system operation, thereby maintaining high-link efficiency over a wide load range. A low-power load modulation signal generator is also developed for closed-loop wireless power control. Implemented in a standard 0.35- CMOS process, the proposed rectifier and ac-dc regulator achieve peak power conversion efficiencies of 92.7% and 88.5%, respectively, while operating at 1 MHz. The proposed autoreconfiguration capability of the regulator further provides the link efficiency enhancement of 28% across the wide load power range from 1 to 20 mW.