A 1.3mA Biphasic Current Stimulator IC with Active Charge Balancing for Nerve Interfacing Applications

作者:Erfani Reza; Marefat Fatemeh; Mandal Soumyajit; Mohseni Pedram*
来源:IEEE International Symposium on Circuits and Systems (ISCAS), 2016-05-22 to 2016-05-25.

摘要

This paper presents a 1.3mA current stimulator integrated circuit (IC) with closed-loop, active charge balancing for nerve interfacing applications. The stimulator employs two current-based digital-to-analog converters (DACs), one each for anodic and cathodic phases, with binary-weighted transistors and 2b-programmable least-significant bit (LSB) currents. The biphasic, cathodic-leading, stimulus current pulse amplitude is 5b-programmable in four ranges of similar to 12-341 mu A, 23-682 mu A, 32-992 mu A, and 42-1,300 mu A. A low-power (similar to 10 mu W), active charge balancer monitors the site voltage after each stimulus cycle and, if necessary, injects positive or negative current pulses via two 3b auxiliary DACs to bring the site voltage back within a user-set safety All digital circuitry operate from 3.3V, whereas the stimulator output stage operates from 5V with a stimulus site common-mode voltage of 3.3V for better use of the available voltage headroom in cathodic-leading, single-supply stimulation. A prototype chip is fabricated in 0.5 mu m 2P/3M CMOS, and measured results from benchtop electrical characterization of the chip are presented.

  • 出版日期2016