22.4 A reconfigurable bidirectional wireless power transceiver with maximum-current charging mode and 58.6% battery-to-battery efficiency

Wireless power transfer (WPT) is currently on the critical point of an explosive growth. Here, as projected in Fig. 22.4.1, we propose a future WPT eco-system of consumer electronics, which includes three layers: 1) wireless charging pads being the fundamental energy plants that can charge a wireless power bank and mobile devices; 2) wireless power banks that get energy from plants and feed mobile devices; and 3) power hungry mobile devices that get energy from all the other sources. To enable the mobile devices charging others without additional hardware, we propose a reconfigurable bidirectional 6.78MHz WPT transceiver (TRX) that reuses the LC resonant tank and 4 area-consuming power transistors for the differential Class-D power amplifier (PA) and the full-wave rectifier. With such WPT TRX embedded, one can provide a first-aid to his/her smart watch or friend's device of which the battery is dying.