A power- and area-efficient integrated power management system for inductively-powered biomedical implants

This paper presents an integrated power management unit (PMU) to improve the power and area efficiencies of the transcutaneous power transmission in biomedical implants. An auto-reconfigurable multi-ratio SC DC-DC regulator is developed within the PMU not only to maintain high system power efficiency under coupling variations but also to reduce the number of required capacitors and power transistors in the system. Implemented in a 0.35-μm CMOS process, the PMU can take an AC input with the signal amplitude of 1.9 V - 3.5 V and provide a regulated output voltage of 4 V. Simulation results show that the proposed PMU can deliver a maximum output current of 10 mA and achieve the peak power efficiency of 83%.