A Fully Balanced Biphasic Neurostimulator with Body-Coupled Powering and Full-Duplex Communication Via Baseband Load Shift Keying

This paper presents a wireless biphasic neurostimulator that exploits body-coupled powering and full-duplex communication, achieving precise stimulation with real-time feedback. Simultaneous wireless power and data transmission can be achieved with a baseband load shift keying. A fully balanced biphasic stimulation can be achieved, whose current is applied using flying capacitors and current regulators, and the residual charge after biphasic stimulation becomes extremely small. Implemented in a 65 nm CMOS, the prototype IC achieves a downlink BER of $1.8 \times 10^{-4}$, an uplink BER of $< 3 \times 10^{-5}$, and a residual charge of 0.22 nC at a depth of 40 mm in porcine tissue.