A low-power digitally closed-loop electrical stimulator suited for low-pulse-width-stimulation

In this paper, a low-power and precise electrical stimulator is introduced in which no operational amplifier (OPAMP) is used. For electrical stimulations that have low pulse width, an OPAMP with high slew rate is needed which is power consuming. In this work, the OPAMP is substituted with a digital circuitry. A 100 KHz clock is also used to update the current of the stimulator in the stimulation phases in order to make the stimulator accurate enough. Producing such a clock needs only few micro watts. This stimulator is simulated in a 0.18 μm CMOS process, as well. The simulation results shows that this stimulator has only 0.056% charge mismatch in 1 mA stimulation current with a pulse width of 32 μs.