A 6.78-MHz Single-Stage Wireless Power Receiver With Ultrafast Transient Response Using Hysteretic Control and Multilevel Current-Wave Modulation

This article presents a 6.78-MHz single-stage regulating rectifier with hysteretic control and current-wave modulation (CWM) techniques for wireless power receiver applications. The proposed receiver realizes ac-dc rectification and dc-dc regulation in a single-power stage, thus improving the power efficiency and reducing the system volume. The hysteretic control together with the proposed CWM technique achieves a much accelerated load-transient response for the rectifier compared to the recently developed multicycle pulsewidth modulation techniques. The system design complexity is significantly reduced. The proposed multilevel CWM technique achieves more evenly distributed power conversions and less output voltage ripples. The proposed receiver fabricated in a 0.18-μm CMOS process using 3.3-V devices can regulate the output voltage to 3.3 V and deliver 1.98-W maximum power with a measured peak efficiency of 92.14%. An instant load-transient response is observed for a load current step between 12 and 600 mA.