Active and passive rectification methods for US-powered IMDs: A comparison in a 28-nm bulk CMOS technology

In this paper the design of power management integrated circuits for the energy harvesting of ultrasound waves in implanted biomedical devices is addressed. In particular, the paper focuses on the main building block of the power conversion stage which is represented by the AC/DC converter. After an in-depth analytical description of cross-coupled passive and active rectifiers, a detailed design procedure for the common-gate comparator is introduced. Then a comparison between the different discussed topologies is carried through simulation results using a 28-nm standard CMOS technology. The results provide useful design guidelines in choosing the best topology according to the design specifications.