Power and Data Management Technology ThrustThe goal of the Power and Data Management Technology Thrust is to develop efficient and adaptive methods of managing power and data for all three testbeds (retinal, neuromuscular and cortical). The thrust’s projects are tied together by four basic themes: power efficiency, bi-directional communication capability, miniaturization, and integration; all of which are fundamental challenges in realizing any implantable microelectronic system. For example, the retinal testbed faces a challenge of maintaining a stable power supply for the implant during coil displacements associated with eye movement. Working with the retinal testbed to determine the range of eye motion, an adaptive power control scheme has been designed that accomplishes this by a closed loop feedback from implant to the external unit.
Led by Wentai Liu, Ph.D.
Since the goal of all the test beds is to realize highly integrated devices (both physically and functionally), inevitably, different projects in the thrust that develop components of the implantable system are highly interdependent. An example of integration is the design of the dual band wireless telemetry for power and data. The relative orientation of the power and data coils greatly affects the received data signal strength. But, the surgery constraints provided by the retinal prosthesis testbed also dictates the position of the coils. The implantable coils preferably should be flexible; this is being done by the interface technology thrust. But generally, microfabricated coils can not match the quality factor of the discrete coils. This creates a multiple constraint problem for the design of the dual band telemetry system. We have developed an approach to select the optimal sizes of the data coils to achieve good signal strength. We are currently performing experiments with prototype coils from Dr. Tai’s group. In the educational front, in winter 2006, we created a cross campus course between USC and UCSC, “Neural Implant Engineering” that is co-taught by Drs. Berger, Liu and Weiland.