24.2 A power-efficient switched-capacitor stimulating system for electrical/optical deep-brain stimulation

Deep-brain stimulation (DBS) has been proven as an effective therapy to alleviate Parkinson´s disease, tremor, and dystonia. Towards a less invasive head-mounted DBS, we utilize an inductive transcutaneous link to provide sufficient power without size, lifetime, and discomfort of chest-mounted battery-powered traditional DBS. The next step is to adopt aggressive power-management schemes to further improve the DBS efficiency. Current-controlled stimulation (CCS) enables precise charge control and safe operation, but it has low power efficiency due to the dropout voltage across current sources [1,2]. Switched-capacitor stimulation (SCS), proposed in [3], takes advantage of both high efficiency and safety using capacitor banks to transfer charge to the tissue, but it requires an efficient on-chip capacitor charging system, directly from the inductive link. We present an integrated wireless SCS system-on-a-chip with inductive capacitor charging and charge-based stimulation capabilities, which can improve both stimulator (before electrodes) and stimulus (after electrodes) efficiencies in DBS.