A power-efficient current-mode neural/muscular stimulator design for peripheral nerve prosthesis

Abstract

This paper presents a 16-channel power-efficient neural/muscular stimulation integrated circuit for peripheral nerve prosthesis. First, the theoretical analysis is presented to show the power efficiency optimization in a stimulator. Moreover, a continuous-time, biphasic exponential-current-waveform generation circuit is designed based on Taylor series approximation and implemented in the proposed stimulation chip to optimize the power efficiency. In the 16-channel stimulator chip design, each channel of the stimulator consists of a current copier, an exponential current generator, an active charge-balancing circuit, and a 24-V output stage. Stimulation amplitude, pulse width, and frequency can be set and adjusted through an external field-programmable gate array by sending serial commands. Finally, the proposed stimulator chip has been fabricated in a 0.18-μm advanced complementary metal-oxide-semiconductor process with 24-V laterally diffused metal oxide semiconductor option. The maximum stimulation power efficiency of 95.9% is achieved at the output stage with an electrode model of 10-kΩ resistance and 100-nF capacitance. Animal experiment results further demonstrate the power efficiency improvement and effectiveness of the stimulator.