An offset‐enhanced active rectifier with delay compensated active diodes for wirelessly powered biomedical implants

Abstract

Abstract This letter presents the design of a 13.56 MHz offset‐enhanced full‐wave active rectifier, tailored for wirelessly powered biomedical implants. The design incorporates digitally assisted, delay‐compensated active diodes and symmetrical bulk biasing in the rectifier core to enhance conduction time, thus improving the voltage conversion ratio (VCR) and power conversion efficiency (PCE). A delay improvement is achieved both in no‐load and high‐load conditions through an additional comparison path with an offset voltage that is higher than zero. The proposed rectifier is implemented and fabricated in a 180 nm CMOS technology with an area of 0.024 mm2. The rectifier, tested and measured with inductive links, offers a maximum VCR of 96.4% and a maximum PCE of 89%.

Keywords

• analogue circuits
• biomedical electronics
• energy harvesting
• rectifiers