Current Controlled CMOS Stimulator with Programmable Pulse Pattern for a Retina Implant

In this work the constant current stimulator of a new epiretinal implant is presented. It consists of a digital waveform generator device, which permits to modify the pulse pattern via a programming interface, a digital–to–current converter, which translates the digital waveform into current pulses with adjustable amplitude, and an output driver, which combines the function of an electrode multiplexer and a high voltage current source for driving large resistive loads. For each of those subcircuits the simulated performance and its designed layout is presented.