A Fully Integrated Single-Stage Wireless Power Receiver With Phase-Shift PWM Control for High Battery-Charging Resolution

This brief presents a phase-shift pulse-width modulation (PWM) control based single-stage wireless charger with constant-current constant-voltage (CC-CV) charging. The proposed wireless charger implements the AC-power rectification, the voltage regulation and the CC-CV charging only in the rectifier stage to realize high receiver efficiency. Compared with the single-stage receiver in the prior arts, the phase-shift PWM control is adopted in order to achieve continuous duty-ratio regulation and improve battery-charging resolution. For the stability enhancement, an analog CC-CV smooth transition technique is introduced to avoid the oscillation during the CC-CV transition, and a DAC-based reference shifter is also adopted. In addition, the sensing speed and accuracy are improved by using a high-performance current-sensing circuit. The proposed charger has been fabricated in a 0.18
$\mu \text{m}$
BCD process. With a charging current range from 100 mA to 200 mA in CC mode, the peak charging efficiency reaches 91.8% in a resonant frequency of 200 kHz.