Wireless Data Transmission Systems for High Channel Count Neural Recording/ Stimulation Microsystems

Abstract:

In the past few decades, there has been a significant progress in the development of wireless data transmission systems, from high data rate to ultra-low power applications, from G-b per second to RFID systems, it has spread its wing to attend to all requests. One specific area, in particular, is in need of wireless data transmission to permit its full potential, and that is implantable bio-medical application.  To understand how brain functions, neural scientists are in the pursuit of high channel count, high density recordings for free- moving animals, yet wire tethering issue has put the mission on pause.

In this work, an ultra-low power ultra-wide band (UWB) transmitter with feedforward pulse generation scheme to resolve the long-existing problem in UWB transmitter is proposed. It provides high data rate capability to enable 1000 channel count broadband neural recording, assuming 10-bit resolution with a sampling rate of 20 kHz for both action potential (AP) and local field potential (LFP) recording, while remaining in ultra- low power consumption at 4.32 pJ/b. Following the transmitter, a bit- wise time -division (B-TDD) duplex transceiver without cancellation scheme is then presented to empower the bi-directional communication between the wireless and recording/ stimulating module. The receiver works at U-NII band and shares the same antenna with UWB transmitter, reducing the area consumption as well as indulging in low power consumption constraint for implantable systems. The system can support uplink at 200 Mbps for 1000 recording channels and 10 Mbps downlink for 36 stimulation channels. With a light weight, 3.7 Volt 25mAh rechargeable battery, it should be able to operate more than 3 hours straight with recording and stimulation channels in mice, assuming 1 LED channel with 100 µA, 10% duty-cycled stimulating current.

The B-TDD transceiver is integrated with our recording/ stimulation optogenetic IC to show as a complete wireless system of implantable broadband optogenetic neural modulation and recording platform. The full integration is less than 5 gram so it is suitable for rodent experiments.

Chair: Professor Euisik Yoon