SMART ENERGY AUTONOMOUS WIRELESS TRANSCEIVER FOR IMPLANTABLE NEURAL INTERFACES
Relevant for Research Area
Prof. Dr. Yiannos Manoli (Contact PI)
The SEAM-WiT project addresses the challenge of designing an efficient versatile telemetry system for providing a bidirectional wireless data- and power link between an external unit and a biomedical implant. The main goals of the overall system are to guarantee the patient’s comfort with a small system volume, a low specific absorption rate (SAR) for avoiding tissue damaging and a high power transfer efficiency for increasing system lifetime. The system architecture includes an external unit (primary side), which can serve as a handheld device, useable by a doctor. This enables to power biomedical implants wirelessly and to accomplish wireless electrophysiological readout, avoiding transcutaneous wired connections. In addi- tion, the system comprises a unit that is intended to be connected to a biomedical implant (secondary side). The primary and secondary sides establish a wireless power and data transmission system. Thus, both units are inductively linked by a pair of coupled coils. The implant side unit comprises an impedance matching circuit, operating the overall system at the maximum efficiency point. This reduces tissue heating and extends the external bat- tery lifetime. Moreover, the SEAM-WiT team also designed a system including a functional integrated circuit (ASIC) that allows managing an exceptionally high power of up to 250 mW. The IC also handles bidirectional wireless data transmission with very high data rates of up to 200 kbit/s. In order to meet the demands of different application scenarios like Parkinson’s disease, epilepsy or stroke a high speed transceiver was also designed. It operates accord- ing to the Medical Implant Communication Service at 403 MHz and allows receiving data with up to 2 Mbit/s, while needing a remarkably low power of 1 mW. Apart from the electronic development and efficiency optimization, a special focus has been set on the miniaturization of telemetric implants. Therefore, a microcoil cleanroom fabrication process has been established and optimized over the whole project period. The process pro- vides the possibility of maximized system integration due to the miniaturization of the im- planted microcoils used for power and data transmission over an inductive link. The process includes the fabrication of planar copper (or gold) microcoils with a footprint of 2×2.5 mm² on a glass substrate of 300 µm in thickness. As a consequence the processed microcoils were assembled to a CMOS chip equipped with an integrated multisensor system and an RF inter- face designed for the available ISM band of 13.56 MHz. This miniaturized telemetric implant was then powered and read out over a distance of ~3 mm with a custom reader unit based on a commercially available RFID integrated circuit (IC). This implant provides a data trans- mission rate of 27.1 kBit/s and requires a power of 17 mW (45 mW for startup). Thus it is an example of an implant with a relatively high power demand and low data rate. Finally, a microcoil was connected to a Polyimide based LED optrode, tuned to resonance at 13.56 MHz, and powered with the designed reader unit. This wireless optrode provides the possibility of animal experiments in smaller test animals with a reduced level of invasiveness due to the possibility of closing the skull completely.
 J. Leicht, D. Rossbach, S. Stöcklin, M. Sherif, J. Hafner, P. Ruther, O. Paul, L. Reindl, M. Kuhl, and Y. Manoli, “System zur kabellosen Daten- und Leistungsübertragung für biomedi- zinische Implantate,” 9.GMM Fachtagung Energieautarke Sensorik, Mar. 2018, Oral Presen- tation.
 S. Stöcklin, T. Volk, A. Yousaf, and L. Reindl, “A Programmable and Self-Adjusting Class E Amplifier for Efficient Wireless Powering of Biomedical Implants,” in Proceedings 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), Aug. 2015, pp. 3193–3196.
 S. Stöcklin, T. Volk, A. Yousaf, and L. Reindl, “Adaptive Elektronik zur effizienten drahtlosen Energieversorgung biomedizinischer Implantate,” in Tagungsband 18. GMA/ITG Fachtagung Sensoren und Messysteme, May 2016, pp. 92–98.
 S. Stöcklin, A. Yousaf, T. Volk, and L. Reindl, “Efficient Wireless Powering of Biomedical Sensor Systems for Multichannel Brain Implants,” in IEEE Transactions On Instrumenta- tion and Measurement, April 2016, Volume 65, Number 4, pp. 754–764.
 S. Stöcklin, T. Volk, A. Yousaf, and L. Reindl, “Efficient Inductive Powering of Brain Im- planted Sensors,” in Proceedings IEEE Sensors Applications Symposium 2015 (SAS 2015), April 2015, pp. 1-6.
 J. Leicht, M. Amayreh, C. Moranz, D. Maurath, T. Hehn, and Y. Manoli, “Electromagnetic Vibration Energy Harvester Interface IC with Conduction-Angle-Controlled Maximum- Power-Point Tracking and Harvesting Efficiencies of up to 90%,” in IEEE International Solid-State Circuits Conference (ISSCC) Digest of Technical Papers , pp. 368 - 369.
 J. Leicht, M. Amayreh, C. Moranz, D. Maurath, T. Hehn, and Y. Manoli, “Electromagnetic Vibration Energy Harvester Interface IC with Conduction-Angle-Controlled Maximum- Power-Point Tracking and Harvesting Efficiencies of up to 90%,” in ISSCC 2015 Demonstration Sessions, [Online]. Available: http://isscc.org/2015-videos/2015. Ac- cessed on: Nov. 5, 2016.
 J. Leicht, M. Amayreh, C. Moranz, D. Maurath, A. Willmann, T. Hehn, and Y. Manoli, “Electromagnetic Vibration Energy Harvester Interface IC with Conduction-Angle-Con- trolled Maximum-Power-Point Tracking and Harvesting Efficiencies of up to 90%,” in Proc. ISSCC 2015 Demonstration Sessions, Feb. 2015, p. 30.
 J. Leicht, and Y. Manoli, “A 2.6 μW–1.2 mW Autonomous Electromagnetic Vibration Energy Harvester Interface IC with Conduction-Angle-Controlled MPPT and up to 95% Efficiency,” IEEE Journal of Solid State Circuits, vol. 52, no. 9, pp. 2448–2462, Sept. 2017.
 J. Leicht, M. Amayreh, Y. Cai, J. Goeppert, F. Hagedorn, T. Hehn, N. Lotze, C. Moranz, D. Rossbach, D. Sanchez, D. Schillinger, and Y. Manoli, “ Energieeffiziente Schnittstellen- schaltungen für (Micro) Energy Harvesting Applikationen,” 2016, Talk, VDC Expert Workshop Energy Harvesting & Energieautarke Systeme.
 T. Hehn, D. Hoffmann, M. Kuhl, J. Leicht, N. Lotze, C. Moranz, D. Rossbach, K. Ylli and Y. Manoli, “Energy-Harvesting Applications and Efficient Power Processing, in CHIPS 2020 VOL. 2 - New Vistas in Nanoelectronics,” 1st ed., ser. The Frontiers Collection, B. Hoefflinger, Ed. Springer, 2016.
 J. Leicht, M. Amayreh, Y. Cai, J. Goeppert, F. Hagedorn, T. Hehn, N. Lotze, C. Moranz, D. Rossbach, D. Sanchez, D. Schillinger and Y. Manoli, “Effiziente Schaltungen und Systeme für Energy Harvesting Anwendungen,” in Programm des 20. Workshops Ana- logschaltungen, Mar. 2018, p. 9.
 S. Stöcklin, T. Volk, A. Yousaf, and L. Reindl, “A Maximum Efficiency Point Tracking Sys- tem for Wireless Powering of Biomedical Implants,” 2015 Eurosensors XXIX, in Procedia Engineering, Volume 120, 2015, pp. 451–454.
 E. Frei, J. Leicht, S. Stöcklin, M. Kuhl, L. Reindl, and Y. Manoli, “Eine Schaltung für die drahtlose Energieversorgung von biomedizinischen Gehirnimplantaten,” in Book of Abstracts Kleinheubacher Tagung 2016, Sept. 2016, p. 79.
 J. Wilmers, J. Leicht, S. Stöcklin, L. Reindl, and Y. Manoli, “Schaltung für die wirkungs- gradoptimierte drahtlose Energieversorgung von biomedizinischen Implantaten,” Klein- heubacher Tagung, Sept. 2018, Oral Presentation.
 D. Schillinger, Y. Hu, M. Amayreh, C. Moranz, and Y. Manoli, “A 96.7% Efficient Boost Converter with a Stand-by Current of 420 nA for Energy Harvesting Applications,” in Pro- ceedings IEEE International Symposium on Circuits and Systems (ISCAS), May 2016, pp. 654–657.
 M. Amayreh, J. Leicht, and Y. Manoli, “A 200ns Settling Time Fully Integrated Low Power LDO Regulator with Comparators as Transient Enhancement,” in Proceedings IEEE Inter- national Symposium on Circuits and Systems (ISCAS), May 2016, pp. 494–497.
 S. Al-Saegh, M. Sherif, and Y. Manoli, “Design of 1mW CMOS OOK Super-Regenerative Receiver for 402-405MHz Medical Applications,” in Proceedings of the IEEE International Symposium on Circuits and Systems (ISCAS), June 2014, pp. 690 – 693.
 M. Sherif, and Y. Manoli, “A Novel Fully Integrated Low-Power CMOS BPSK Demodu- lator for Medical Implantable Receivers,” in Proceedings of the IEEE International Sym- posium on Circuits and Systems (ISCAS), June 2014, pp. 1098 – 1101.
 M. Sherif, and Y. Manoli, “Design and Implementation of an RF CMOS Differential LNA for 403MHz Applications,” in Proceedings of the IEEE International Symposium on Cir- cuits and Systems (ISCAS), June 2014, pp. 1400 – 1403.
 M. Sherif M, and M. Ortmanns, “Basics, Regulations and Implementation of Data Te- lemetry for Implants,” 2014 Tutorial, IEEE International Symposium on Circuits and Sys- tems (ISCAS).
 M. Kuhl, M. Keller, N. Muller, B. Shui, S. Mohamed, O. Cota, D. Rossbach, A. Taschwer, and Y. Manoli, “Entwurf neuronaler Schnittstellenschaltungen – Mikroelekt- ronik im Exzellenzcluster BrainLinks-BrainTools,” 2015, Talk, Workshop Analogschal- tungen.
 J. Hafner, M. Kuhl, M. Schwaerzle, T. Hehn, D. Rossbach, and O. Paul, “Fabrication of Planar Copper Microcoils for Telemetric Orthodontic Applications,” Proceedings Eu- rosensors, vol. 1, no. 4, p. 571, Aug. 2017.
 J. Hafner, O. Paul, “First Telemetric Orthodontic Bracket for Therapeutic Applications,” Proceedings IEEE Sensors Conference, 2018, pp. 574-577.
 J. Hafner, “Fabrication of Copper Microcoils for the First Smart Smart Bracket with Sufficient Readout Distance”, Poster Contribution, Micro Alliance Workshop, Freiburg, 2018.
 J. Hafner, “Fabrication of Planar Copper Microcoils for Telemetric Applications”, Poster Contribution, NAMIS Workshop, Freiburg, 2017.