Powering Implanted Wireless Brain-Machine Interfaces

Michael Mark and Jan M. Rabaey

California Energy Comission

The concept of implanted brain-machine interfaces (BMI) has gathered a lot of momentum in the past years. Ideally these devices operate completely wirelessly making any wires through the skin obsolete to reduce any risk of infection and increase the patient`s comfort at the same time [1]. The potential impact of such interfaces is absolutely huge, leading from advanced prosthetics over micro-stimulation for treatment of certain brain illnesses to complete new user interfaces. Researchers at various institutions have already made major progress in the implementation of electrode arrays, signals acquisition techniques and communication links. One big challenge that is often overlooked though is how to power such devices. The size of an implant is ideally dictated by the size of the electrode array which can vary between 1 – 100 mm², depending on the application and kind of electrode. The goal of this research is to determine the maximum available power for a given overall size constraint in the range of 1 x 1 – 10 x 10 mm² and build systems in standard 65nm CMOS that deliver this power to the implant.

Figure 1
Figure 1: A possible application: A fully implanted wireless BMI used to control an arm prosthesis [1]

Figure 2
Figure 2: Block Diagram of a Generic Wireless Neural Implant

Mikhail A. Lebedev, Miguel A.L. Nicolelis, Brain-machine interfaces: past, present and future, Trends in NeurosciencesVolume 29, Issue 9, , September 2006, Pages 536-546. (http://www.sciencedirect.com/science/article/B6T0V-4KFV367-2/2/1c479d63267ad95d2a57070bfd516003)