A CMOS Rectifier With a Cross-Coupled Latched Comparator for Wireless Power Transfer in Biomedical Applications

A highly efficient rectifier for wireless power transfer in biomedical implant applications is implemented using 0.18-mu m CMOS technology. The proposed rectifier with active nMOS and pMOS diodes employs a four-input common-gate-type capacitively cross-coupled latched comparator to control the reverse leakage current in order to maximize the power conversion efficiency (PCE) of the rectifier. The designed rectifier achieves a maximum measured PCE of 81.9% at 13.56 MHz under conditions of a low 1.5-V-pp RF input signal with a 1-k Omega output load resistance and occupies 0.009 mm(2) of core die area.