All Wireless, 16-channel Epilepsy Control System with Sub-mu W/channel and Closed-loop Stimulation Using a Switched-Capacitor-Based Active Charge Balancing Method

An all wireless closed-loop stimulation system for epilepsy control is presented that generates charged-balanced programmable stimulation current pulses upon a seizure is detected. The proposed system has highly flexible stimulation parameters thanks to the proposed switched-capacitor-based charge balancer (SCCB). The proposed active charge balancer is able to generate both charge-balanced symmetric and asymmetric stimulation pulses without requiring additional charge balancing phase. The straightforward design of the SCCB consumes low silicon area and low power consumption (4.7 mu W). The proposed charge balancer has an accurate and safe performance with a maximum remaining voltage of 25 mV. Furthermore, the structure of multi-input single-output compressive sensing (MISOCS) block proposed in this paper, improves the detection quality. The seizure detector of the proposed system has a sensitivity of 100% and false alarm rate of 0.09/h. The proposed system is implemented and validated using a 0.18 mu m technology.