MCU-less biphasic electrical stimulation circuit for miniaturized neuromodulator.

A standalone neuro-stimulator circuit without a need of microcontroller (MCU) is presented. The neuro-stimulator circuit has a capability to produce a biphasic electrical stimulus with programmable pulse width and train duration. The proposed hardware system consists of commercial-off-the-shelf (COTS) components: a comparator to recognize triggering events and generate on/off signal for a variable train duration, a programmable timer to generate oscillatory signal with a fixed frequency and a variable pulse width, and a differentiator to convert monophasic pulses to biphasic pulses. The differentiator also works as a current driver having current drive capability of up to 40 mA. The proposed MCU-less biphasic electrical neuro-stimulator successfully generated biphasic stimuli with variable pulse widths from 400 µs to 5 ms and train durations from 35 to 55% of cycle duration. It works with fixed parameters programmed at the beginning, and does not need continuous MCU input. Therefore, the proposed standalone neuro-stimulator circuit has a potential to decrease power and area consumption and minimize the size of the neuro-stimulator system. © Korean Society of Medical and Biological Engineering 2022.