Current-limited passive charge recovery for implantable neuro-stimulators: Power savings, modelling and characterisation

In this paper, we investigate a passive charge recovering stimulation strategy that can potentially halve the stimulation power consumption in implantable neuro-stimulators. We propose a simple circuit implementation and an electrode-tissue interface model and use this to simulate average electrode currents and electrode resting potentials over a range of stimulation and electrode parameters. We compare said measures with same for a capacitively coupled stimulation strategy and a post-stimulation electrode shortening strategy finding that the passive charge recovering strategy is comparable to post-stimulation shortening. The simulations are confirmed with in-vitro measurements in physiological saline.