A 200-Mb/s Energy Efficient Transcranial Transmitter Using Inductive Coupling.

Area of Science:

• Biomedical Engineering
• Electrical Engineering
• Implantable Devices

Background:

• Neural implants require efficient wireless communication for data transmission.
• Existing wireless transmitters often face challenges with power consumption and data throughput.

Purpose of the Study:

• To develop an energy-efficient wireless transmitter (TX) for neural implant applications.
• To achieve high data throughput and reliable communication through biological tissues.

Main Methods:

• Utilized inductive coupling with a de-Q'ed TX inductor for high throughput.
• Implemented an ultra-low power injection-locked phase lock loop (PLL) with background frequency calibration for clock generation.
• Fabricated the TX chip in a 65-nm CMOS process with custom PCB inductors.

Main Results:

• Achieved a data throughput of 200 Mb/s.
• Demonstrated a bit error rate (BER) of 5e-11 through 11.8 mm of piglet skull and <1e-12 BER over an 11 mm air gap.
• The TX chip consumed only 300 μW from a 0.5 V supply, resulting in 1.5 pJ/b energy efficiency.

Conclusions:

• The developed wireless transmitter is highly energy-efficient and suitable for neural implants.
• The design demonstrates robust performance through biological tissue, crucial for in-body communication.
• This technology advances the potential for sophisticated and long-term neural interfacing.