The design of output stage circuitry for constant current neuromuscular stimulation

A 16-channel analog hybrid circuit has been designed, manufactured, and tested to provide functional neuromuscular stimulation to individuals with spinal cord injuries. The circuit generates a constant current, charge balanced, biphasic, asymmetrical waveform for both percutaneous and surface stimulation via the use of external current setting resistors, capacitors, and control circuitry. Currents from 1 to 100 mA have been achieved with pulsewidths from 1 to 255 ms and interpulse intervals of 20-100 ms. The analog hybrid circuit is packaged in a 32-pin pin-grid-array package approximately 0.9 in.*0.9 in.*0.2 in. in size.<>