2.4-GHz High-Efficiency Adaptive Power

A 2.4-GHz high-efficiency adaptive rectifier with extended input power range is presented. The rectifier consists of two differential-type sub-rectifiers and a control circuit. The proposed control circuit can detect the input power level by sensing the converted output voltage of the rectifier and then generating two control signals to switch the rectifier between two operation modes. This device has been fabricated in 0.18- μm CMOS technology. With two three-stage differential-type rectifiers as the sub-rectifiers, the optimal power conversion efficiency (PCE) region is extended to 11 dB by the proposed technique under a 2- kΩ load. Moreover, the proposed rectifier has two peak PCEs, which are 47% and 41% at input powers of 8.9 and 2.1 dBm, respectively.