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 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1.8 \times 10^{-4}$</tex>, an uplink BER of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$&lt; 3 \times 10^{-5}$</tex>, and a residual charge of 0.22 nC at a depth of 40 mm in porcine tissue.