Loss Analysis and Heat Optimization for a 700-mW Inductive Power Transfer System for Implanted Brain-Computer Interface

The growing power demands of implantable medical devices, particularly brain-computer interfaces (BCIs), have driven the adoption of inductive power transfer (IPT) as a reliable and efficient energy delivery method. This paper presents a comprehensive methodology to identify, evaluate, and mitigate ECL in implantable BCIs. Starting from a practical case study, an ECL model is developed to decouple the influence of excitation current and isolate dominant loss mechanisms. A novel identification framework is introduced for efficient analysis, comparison, and measurement of ECL. Through a combination of simulation and experimental validation, both conduction and eddy current losses are optimized independently. Finally, a representative BCI system is co-optimized for coil geometry, wire selection, and phase control to minimize heat generation. This work offers a systematic solution to mitigate thermal risks in next-generation high-power implantable devices.