A New Wireless Power-Transfer Circuit for Retinal Prosthesis

This paper presents a novel resonant power converter for transcutaneous power transmission in retinal prosthesis applications. In retinal prosthetic applications, the frequency and power of the transmitted signal must be limited to a specific range such that the living tissue is not harmed. The design goal is to transmit power with maximum efficiency, and minimum sensitivity to the nonideal power transfer link. The proposed wireless power-transfer circuit offers significant advantages over conventional ones, which usually use Class E converters. The proposed approach has very low sensitivity to coupling factor/load variations in the inductive link and demonstrates very fast dynamic response. In addition, the proposed approach does not require a dc-dc converter to control the output power. Soft switching is achieved for the proposed circuitry despite the variations in the coupling coefficient. Thus, superior efficiency can be obtained using the proposed approach. Theoretical analysis and various simulations validate the superior performance of the proposed approach. In addition, a 1-MHz experimental prototype has been prepared to verify the feasibility of the proposed wireless power-transfer circuit.