Use of multi-coil telemetry system for high tolerance efficient wireless power system

Inductive link based wireless power transfer (WPT) is a common method for powering implantable electronics. The efficiency of a WPT system depends on the driver resistance and the effective resistance of the implant. In different operation modes of implant electronics, the effective load resistance varies causing significant variation in efficiency. In this work, a multi-coil based WPT system is proposed to improve the tolerance of the power transfer efficiency due to variation in source and implant resistance. For the same physical dimensions, the multi-coil system shows twice the better efficiency tolerance than a traditional two-coil based WPT system.