This article presents a power management integrated circuit for a wireless power receiver unit. A dual-mode high-efficiency active rectifier design is based on alliance for wireless power (A4WP) and wireless power consortium (WPC) standards. A gate charge recycling technique is proposed in the dual-mode active rectifier so that the current generated by the switching of the high side gate driver can be recycled to the rectifier output voltage in order to enhance efficiency. A step-down dc–dc converter with a proposed bootstrap circuit and dynamic pull-up resistor gate driver circuit is designed. The chip is implemented in a 0.18-μm bipolar-CMOS double-diffused metal-oxide-semiconductor process. The total die area, including the pad, is 2.64 mm × 2.6 mm. The measurement results show that the active rectifier achieves peak power conversion efficiency (PCE) of 94.7% and generates an output voltage of 7.68 V in WPC mode and 9.1 V with 93.4% efficiency in A4WPC mode. The input voltage varies from 10 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P-P</sub> –12 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P-P</sub> . Similarly, the step-down dc–dc converter obtains a peak PCE of 93.2% at a load current of 500 mA while producing an output voltage of 5 V. The overall system efficiency at A4WP and WPC mode are 86.7% and 88.2%, respectively.