A monolithic programmable nerve/muscle stimulator

This paper presents a monolithic single-channel programmable nerve/muscle stimulator implemented in a 0.35μm CMOS technology. It consists of a 10-bit current output digital-to-analog converter (DAC) to generate the required cathodic and anodic currents, and a simple digital circuit to control the operation of the stimulator and its programmable stimulation parameters. The proposed stimulator produces balanced biphasic current pulses, with programmable amplitude, frequency and pulse width. The experimental results show that the stimulator can provide cathodic current with amplitudes ranging from 10μA to 10mA, and adjustable pulse widths from 8μs to 120μs at a clock of 125kHz. The amplitude of the anodic current s designed to be half of the cathodic current to facilitate charge balance. The measured charge mismatch is less than 63nC.