A Current Monitoring and Over-Current Detection Circuit for Safe Electrical Stimulation

Abstract

This brief presents an integrated solution to overcurrent protection in neuromuscular stimulators. The proposed approach provides fast detection of a single-fault condition, i.e., unintentional electrode short circuit or malfunction of the stimulator, thereby preventing prolonged high-intensity currents from flowing into tissues. In addition, a programmable current threshold enables the system to be also used for monitoring the stimulation intensity. The proposed solution was designed in a 180 nm high-voltage CMOS technology, and its functionality was verified by post-layout simulations in which the safety mechanisms were tested under fault conditions. The implementation only occupies an area of 0.286 mm 2 , making it feasible to be embedded in fully integrated NMES stimulators while providing the required patient safety.