A Wide-Input High-Accuracy CMOS Peak Detector for WPT Systems

In this paper, a CMOS peak detector based on a rail-to-rail comparator and an asymmetric charge pump is proposed for wireless power transfer (WPT) systems. To realize wide input range, a novel rectifier stage with bulk bias and a rail-to-rail comparator are applied. Besides, combined with the high-speed comparator, an asymmetric charge pump is adopted to enhance the accuracy. In addition, a new up/down feed-forward path is proposed to improve transient response. The peak detector is designed and fabricated with 0.18μm CMOS process. As the simulation results show, the peak detector can detect the input peak voltage ranging from 0.5V to 4.5V with 1.8% maximum accuracy, and realize 1.6/1.5μs@1V rise/fall time with 83.6μA current consumption.