One-time-implantable spinal cord stimulation system prototype

A prototype of a one-time-implantable spinal cord stimulation (SCS) system using wireless power and data-transmission techniques is presented in this paper. The power of the implant is induced by wireless coil coupling, and duplex amplitude-shift keying-load-shift keying wireless communication is used so that digital packets can be transmitted by the same inductive link. The proposed novel ASK demodulator attains high demodulation performance and small area without using any resistors and capacitors. The proposed SCS system utilizes many power saving schemes to reduce power dissipation (e.g., dual supply voltages on-chip, high-voltage impulse generation using small current, etc.). Meanwhile, the excess energy induced by the coils is stored in a rechargeable battery to extend the implant's operation time so that the number of battery replacement surgeries will be reduced significantly. The system-on-chip (SOC) is physically implemented on silicon and integrated in the implant as the system controller. The fabricated SOC area is 1410 × 1710 μm(2). Compared with existing commercial products, the proposed SCS system attains better flexibility and longer operation time.