A smart bi-directional telemetry unit for retinal prosthetic device

This paper describes a smart bi-directional telemetry unit for an implantable retinal prosthetic device. The system is designed to deliver 250 mW to the intra-ocular unit via an inductive link and provide wireless communication capability. A novel dual frequency carrier approach is used to optimize the power link for maximum transfer efficiency and the forward telemetry for high data rates. The power link uses a smart feedback system via reverse telemetry to compensate for instantaneous changes in power level due to coil misalignment and load variations. The system is optimized to minimize the power losses in the analog front-end of the intraocular unit while ensuring proper device operation. Preliminary results are shown in AMI 1.6 /spl mu/m bulk CMOS process for the reverse telemetry and power feedback system.