A 16-channel Neural Stimulator IC with DAC Sharing Scheme for Artificial Retinal Prostheses

Abstract

Abstract-The neural stimulators have been employed to the visual prostheses system based on the functional electrical stimulation (FES). Due to the size limitation of the implantable device, the smaller area of the unit current driver pixel is highly desired for higher resolution current stimulation system. This paper presents a 16-channel compact current-mode neural stimulator IC with digital to analog converter (DAC) sharing scheme for artificial retinal prostheses. The individual pixel circuits in the stimulator IC share a single 6 bit DAC using the sample-and-hold scheme. The DAC sharing scheme enables the simultaneous stimulation on multiple active pixels with a single DAC while maintaining small size and low power. The layout size of the stimulator circuit with the DAC sharing scheme is reduced to be 51.98 %, compared to the conventional scheme. The stimulator IC is designed using standard 0.18 μm 1P6M process. The chip size except the I/O cells is 437 μm ´ 501 μm.

Design and implementation of 4 bit binary weighted current steering DAC

“…DACs are often used to convert finite-precision time series to a varying physical data. These are mainly used in different applications like data distribution and acquisition systems, amplifier, Electronics display [1][2][3][4][5][6][7].…”