Time-Shifted Control of Self-Synchronous Rectifier For MHz Wireless Power Transfer Systems

Recently wireless power transfer systems via resonant magnetic coupling (MRC-WPT) is the promising wireless power supply method to mobile applications. 13.56MHz highly resonant wireless power receivers experience high rectifier losses when using Schottky diodes and can fail to meet the thermal limit requirements for many products such as laptops. Therefore, the synchronous rectification is one of the effective solutions. However, the increased occupancy of the control signal propagation delay in switching cycle, tend to make the introduction of the synchronous rectification difficult. This novel synchronous rectifier can operate under any propagation delay of gate drivers. The analysis successfully verified the operating principle and clarified the usefulness of the proposed control for MHz WPT systems.