Retinal Stimulator ASIC Architecture Based on a Joint Power and Data Optical Link

Retinal implants aim to partially restore vision to patients suffering from blindness caused by age-related macular degeneration (AMD) or retinitis pigmentosa (RP). Up until now, most prostheses were powered using an inductive link coupled with cables penetrating through the eyeball. Although they efficiently power the implant, they limit long-term reliability and cause postoperative complications. A fully wireless near-infrared power and data link entering the eye through the pupil alleviates these issues but limits the available power and causes energy supply interruptions during blinking. This article presents a retinal implant ASIC architecture optimized for optical operation despite these constraints. It contains 288 individually controlled electrode drivers, each connected to electrode pads with a pitch of 150 μm. A digital controller with a stateless communication scheme allows flexible stimulation sequences and is capable of restoring stimulation within 3 ms after an eye blink. The prototype was fabricated using a CMOS 65-nm low-power technology and occupies an area of 2.8 × 3.1 mm
²
with a static power consumption of 3.1 mW.