A Reconfigurable Single-Stage Asymmetrical Full-Wave Step-Down Rectifier for Bidirectional Device-to-Device Wireless

Abstract

This article proposes a reconfigurable single-stage regulating asymmetrical full-wa ve step-down rectifier (SDR) for fast wireless charging. The SDR is reconfigurable into a step- up power amplifier (SUPA) for device-to-device (D2D) wireless charging. The SDR and SUPA can have a direct connection with the battery without an additional voltage regulator module (VRM). With the single-stage st ructure, the transmitting (TX) and receiving (RX) ac voltages across the resonant coil can be boosted, which greatly reduces the coil currents and losses, improving the D2D charging power. A reconfigurable controller for the TX/RX mode selection, as well as the switching timing control, is designed. The chip is fabricated in 0.35- µmC M O S that contains 20-V devices. For the asymmetrical operation, one GaN device is used for the high current path. Also, zero-voltage switching (ZVS) is realized for all the power transistors with one small (180 nH in the 4015 package) power i nductor. The bidirectional D2D WPT system achieves a maximum charging power of 5.1 W with a D2D total efficiency of 46.3% and a charging distance of 1.6 cm. Finally, the peak total efficiency is 51.4% with a charging power of 3.4 W and a charging distance of 1 cm.