A fully-integrated high-compliance voltage SoC for epi-retinal and neural prostheses.
This paper presents a fully functionally integrated 1024-channel mixed-mode and mixed-voltage system-on-a-chip (SoC) for epi-retinal and neural prostheses. Taking an AC input, an integrated power telemetry circuits is capable of generating multiple DC voltages with a voltage conversion efficiency of 83% at a load of 100 mW without external diodes or separate power integrated circuits, reducing the form factor of the prosthetic device. A wireless DPSK receiver with a novel noise reduction scheme supports a data rate of 2 Mb/s at a bit-error-rate of 2 ×10⁻⁷. The 1024-channel stimulator array meets an output compliance voltage of ±10 V and provides flexible stimulation waveforms. Through chip-clustering, the stimulator array can be further expanded to 4096 channels. This SoC is designed and fabricated in TSMC 0.18 μm high-voltage 32 V CMOS process and occupies a chip area of 5.7 mm × 6.6 mm. Using this SoC, a retinal implant bench-top test system is set up with real-time visual verification. In-vitro experiment conducted in artificial vitreous humor is designed and set-up to investigate stimulation waveforms for better visual resolution. In our in-vivo experiment, a hind-limb paralyzed rat with spinal cord transection and implanted chronic epidural electrodes has been shown to regain stepping and standing abilities using stimulus provided by the SoC.
Yi-Kai
YK
Lo
Kuanfu
K
Chen
Parag
P
Gad
Wentai
W
Liu
D000818:Animals; D004558:Electric Stimulation / Q000295:instrumentation*; D004567:Electrodes, Implanted; D004582:Electronics, Medical / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D006801:Humans; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation; D008954:Models, Biological; D058117:Neural Prostheses; D051381:Rats; D017207:Rats, Sprague-Dawley; D013686:Telemetry / Q000295:instrumentation; D057488:Visual Prosthesis; D014822:Vitreous Body / Q000502:physiology