22.6 A 22V compliant 56µW active charge balancer enabling 100% charge compensation even in monophasic and 36% amplitude correction in biphasic neural stimulators

Abstract

Functional electrical stimulation (FES) is a technique that stimulates nerves by electrical charge, but carries the risk of charge accumulation, voltage pile-up, electrode corrosion and finally tissue destruction. Using biphasic stimulus current pulses, the main transferred charge is compensated by reversing the current direction. However, due to PVT variations in integrated circuits mismatch in the biphasic waveform always occurs. Charge balancing (CB) has thus become an integral part of FES to ensure safe chronic stimulation [1].