A Current-Mode Wireless Power Receiver With Optimal Resonant Cycle Tracking For Implantable Systems

Continuous health monitoring has become feasible, largely due to miniature implantable sensor systems such as [1]. To recharge batteries of such systems, wireless power transfer is a popular option since it is non-invasive. However, there are two main challenges: 1) strict safety regulations of incident power on human tissue; 2) small coil size for better biocompatibility. These issues reduce the received power at the coil, make it difficult to obtain sufficient power for implanted devices, and call for high power-efficiency (ηP)-transfer techniques, especially at very low received power levels.