A fully integrated energy-aware baseband circuitry for next-generation retinal implants

The state-of-the-art prosthetic devices have been successfully approved as critical approach to provide at least partial reconstruction for physiological diseases by replacing a damaged tissue or organ. Invariably, they are always aspired to have lower power consumption despite the battery or the battery-less implementation. This paper presents an energy-aware baseband circuitry concerned about the next-generation multi-channel prostheses especially for the retinal implant in which an inductive-coil link is preferred to fulfill the need of power delivery for providing safer tissue-machine interfaces in the intraocular environment. The extended lifetime for those of the battery-dependent implants can be also achieved by adopting such a power-efficient scheme. The proposed system is a 16-channel-based on-electrode multiplexing design, which can deal with up to 40 frame/sec with 240 stimulus channels in mode I and 3 times the resolution at the same frame rate in mode II under a carrier frequency of 2 MHz. A prototypical chip was implemented in a 0.18-μm CMOS process and the experiment has also been carried out as proof of concept.