Programmable current source dedicated to a cochlear implant

In this paper, a novel architecture of a programmable current-source based on miniaturized digital-to-analog converters (DAC) was proposed. Such new design would be dedicated to cochlear implant circuit. In this study, our main objective was to look for one model that could include, as close as possible, several criteria related to the implant functionality such as reliability, flexibility, energy efficiency and integration area. Hence, this 6-bit DAC architecture was conceived in order to be adequate for a programmable current-source. Our design was able to generate a 2mA maximum current through a 1KΩ load, which is around the typical nerve impedance. Simulation results showed good linearity, low power consumption and a low area occupation. Resulting circuit was simulated by PSPICE tool using the 0.35μm CMOS technology.