Design of Integrated Neural/Modular Stimulators

Abstract

This thesis focuses on the power efficiency improvement of the neural/muscular stimulator and the cancellation of the artifacts introduced by the stimulation. A current-mode neural/muscular stimulator with an exponentially decaying stimulation current is first described. A simple exponentially decaying current generator is proposed based on Taylor series approximation and implemented in a 16-channel prototype stimulator IC. The prototype IC is fabricated in a 0.18-?m CMOS process and the measured results show that maximum stimulation power efficiency of 95.9% can be achieved at the output stage of the stimulator. In the second part of the thesis, an artifact-suppression technique based on a referenced and tuned push-pull stimulation (RTPPS) scheme with a tri-polar electrode is presented. A prototype recording and stimulation system is designed to demonstrate the proposed artifact-suppression. The amplitude of the measured stimulation artifact is suppressed to only 10%-20% of the neural spikes to be recorded in the animal experiment.