Programmable high-amplitude balanced stimulus current-source for implantable microstimulators

In this paper, a 5 bit programmable current-source dedicated to implantable microstimulators is presented. Generating a maximum current of 4 mA through a 1 K/spl Omega/ load, it takes advantage of the BiCMOS 0.8 /spl mu/m technology which allows high current-level output-stage. It occupies a silicium area smaller than 0.026 mm/sup 2/. Simulation results showed good linearity and low power consumption. Its architecture allows the generation of bi-directional current pulses and features an almost null DC offset. Finally, the proposed current-source can be easily modified to output a smaller current range, enabling greater precision and giving the possibility to stimulate nerves with higher impedances.