High Power Factor Wireless Power Transfer Front-End Circuit for Heterogeneous Systems

This paper investigates a high power factor switch-based wireless power transfer front-end circuit for heterogeneous systems. This circuit uses an integrated switching rectifier, implemented in 0.18um 1.8V/5V CMOS process. An integrated pair of phase synchronizers is used to align the waveshape of a wirelessly-coupled sinusoidal voltage source in the receiving coil to the corresponding conducting current. Using this approach, the power factor can be increased above 0.9 without requiring any wireless or wired feedback to the transmitter. The integrated switching rectifier can also provide: ac-dc rectification; facilitate the deployment of multi-receiver to single-transmitter wireless power transfer; and have the capability for voltage up and down conversion of the peak amplitude of the sinusoidal voltage source by use of a pulse-width modulation controller. From measured results, the output voltage can be stepped down from 1.65V to 1.08V and stepped up from 1.5V to 1.68V. Also, the measured power factor is 0.9 when the conducting current is managed at continuous conduction mode.