A 6.78MHz Dual-Output Wireless Transfer System With Adaptive Global Power Control for Efficiency Enhancement.

This paper presents a novel single-stage dual-output wireless power transfer system with an adaptive global power control. The power of freewheeling mode mentioned in the traditional reconfigurable regulating rectifier is used as another output, which achieves high light-load power conversion efficiency (PCE) of the receiver. The voltage of one channel is regulated by a local constant on-time control, while another channel is regulated by the adaptive global power control. In this way, all of the received power is almost transmitted to the output. This proposed wireless power transfer system is designed in a 0.18 mu m BCD process, and regulates two outputs voltage of 4 V each. The maximum output power is 840 mW with a peak PCE of 93.1%. Compared with the local voltage-regulation, the light-load efficiency improvement reached 17.5%.