Load optimization of an inductive power link for remote powering of biomedical implants

This article presents the analysis of the power efficiency of the inductive links used for remote powering of the biomedical implants by considering the effect of the load resistance on the efficiency. The optimum load condition for the inductive links is calculated from the analysis and the coils are optimized accordingly. A remote powering link topology with a matching network between the inductive link and the rectifier has been proposed to operate the inductive link near its optimum load condition to improve overall efficiency. Simulation and measurement results are presented and compared for different configurations. It is shown that, the overall efficiency of the remote powering link can be increased from 9.84% to 20.85% for 6 mW and from 13.16% to 18.85% for 10 mW power delivered to the regulator, respectively.