Programmable Pulse Generator for Pain Relief Stimulation using Bioresorbable Electrodes

Neurostimulation therapies are often applied as an alternative method to pharmaceutical treatment for chronic pain relief. This paper demonstrates the design and implementation of a programmable Pulse Generator (PG) for analgesic nerve stimulation with 3 modes of operation: biphasic asymmetric, biphasic capacitor coupled, and monophasic Degradation On Command (DOC). The PG is implemented on 180nm CMOS technology and could generate up to ± 4mA current pulses in steps of 31μA (8-bit resolution) for pulse duration range of 1-256μs and stimulation frequency range of 16Hz-250kHz. During in vitro studies, capacitor-coupled biphasic stimulation provides electrode stability with only 5Ω impedance change for up to 14 million pulses. In the DOC mode, accelerated degradation of a bioresorbable electrode was observed after 24hrs of stimulation, when its impedance increased from about 100Ω to over 0.2MΩ at 500Hz. The compact, tunable and battery-powered pulse generator printed circuit board (PCB) shows promising results to perform in vivo animal studies for up to 30 hours of continuous stimulation with 26.4mW peak power consumption.