Parallel multiplexing--a solution of large scale stimulation needed by the retinal prostheses to maintain the persistence of vision.
Since retinal prosthesis has been able to stimulate a limited number of neurons (around 100) by the biphasic current stimulus to reproduce an image spatially by multiplexing technique. For functional restoration of sight (visual acuity 20/80) we are to stimulate at least 2500 neurons/mm2. We are far behind that target. The time required by biphasic stimulus, and sequential stimulation by multiplexing technique limits our ability to stimulate a large number of neurons, and maintain the persistence of vision. We have designed a stimulus circuit applying parallel multiplexing technique, which is capable of simultaneous stimulation of a large number of cells. This paper presents an implantable CMOS-based 5x5 array prosthesis to demonstrate that idea. This 5x5 array prosthesis is scalable to a larger array. It uses external clock for its timing making it suitable for any data rate. It has a programmable biphasic width controller (BWC), which can generate monophasic or biphasic current stimulus with or without interphase delay. The chip has been fabricated using 0.5 microm CMOS technology and tested.
Talukder
Mohammad I
MI
Wayne State Univ., Detroit, MI 48202, USA.
Siy
Pepe
P
Auner
Gregory W
GW
D001185:Artificial Intelligence; D004599:Electric Stimulation Therapy / Q000295:instrumentation* / Q000379:methods; D004567:Electrodes, Implanted; D019544:Equipment Failure Analysis; D006801:Humans; D008839:Microelectrodes; D019736:Prostheses and Implants; D011474:Prosthesis Design; D012160:Retina / Q000503:physiopathology*; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D013813:Therapy, Computer-Assisted / Q000295:instrumentation / Q000379:methods; D014786:Vision Disorders / Q000503:physiopathology* / Q000534:rehabilitation*