CMOS stimulating chips capable of wirelessly driving 473 electrodes for a cortical vision prosthesis

Area of Science:

• Biomedical Engineering
• Neurotechnology
• Implantable Devices

Background:

• Implantable neural devices offer restoration of function for disabled patients.
• High power consumption and data needs of multi-electrode implants necessitate batteries or wiring, posing limitations and risks.
• Current limitations include size, longevity, infection, and mechanical damage.

Purpose of the Study:

• To overcome limitations of current neural implants.
• To design and implement a wirelessly powered system with individually controlled microelectrodes.
• To reduce risks associated with implanted devices.

Main Methods:

• Developed a system supporting up to 473 implanted stimulating microelectrodes.
• Utilized micropower application-specific integrated circuits (ASICs) for individual electrode control.
• ASICs were designed for wireless power and low power consumption.

Main Results:

• Each ASIC controls 43 electrodes, consuming 3.18 mW when stimulating 24 channels.
• Measured digital-to-analog converter (DAC) linearity at 0.21 LSB (integrated non-linearity).
• Observed stimulation pulse timing variability across ASICs of 172 ns.

Conclusions:

• Demonstrated the feasibility of a novel low-power ASIC for human visual cortex implantation.
• The fully implantable system significantly reduces infection and mechanical damage risks.
• This technology holds promise for improving quality of life through advanced neural stimulation.