Transmitter IC Enabling Magnetic Field Shaping for High-Efficiency Wireless Charging of Multiple Receivers.

In this paper, we introduced two transmitter (TX) integrated circuits (ICs) which enabled magnetic field shaping for high-efficiency wireless charging. Through the control of the amplitude and phase of current in multiple TX coils, the generated magnetic fields were optimally shaped for the efficiency (η SYS ) maximization. This method was advantageous for the wireless charging of not only a single receiver (RX) but also multiple RXs. Both ICs were fabricated by a 0.18 μm CMOS process with 1.8 V devices and related wireless power transfer (WPT) systems were implemented. Experimental results demonstrated that the proposed ICs enabled improvements in η SYS and load power in WPT systems whether RX coils were perpendicular to or parallel with TX coils.