Ifi Research: Microelectronic Systems: Nanooelectronic Systems: Neuromorphic Systems: Student Projects
This is a project in connection with a collaboration with the company LifeCare. The aim of the collaboration is to develop a glucose sensor that is implantable and allows continuous monitoring of glucose levels in the blood of diabetes patients. The continuous monitoring allows a finer administration of insulin and avoids big swings in the glucose levels. The later have severe consequences on the patients health in the long run. By avoiding these swings the life expectancy of the patients can be increased by several years.
A permanent implant cannot require cables through the skin. Thus, the communication and the supply with energy has to be wireless. We intend to solve this with an inductive link, i.e. two coils, one on the skin and the other just under the skin. This solution has been used already very successfully for example in cochlear implants. The coils allow an AC signal to be transfered through the skin. One component of the inside has to transform this AC signal into a stable, temperature independent DC power-supply for the implant with as big an efficiency as possible.
The power receiver on the implant is a resonant circuit that needs to be tuned to the same resonance frequency as the unit outside the body that sends the power. the resonance frequency depends on the implant coil's inductance and a capacitance (also implemented on the implant). The inductance of the coil on the implant however, does vary quite a bit as the implant is produced. it is, thus, highly desireable to be able to compensate this variation in inductance by being able to calibrate the capacitance of the resonant receiver circuit.
The aim of this project is to design a programmable capacitance onto the CMOS integrated circuit using non-volatile memory, i.e. flash-ROM. It will involve ASIC and PCB design and testing. A perticular difficulty in this design is the fact that the capacitance needs to be operational without power-supply, since the power receiver (of course) needs to be able to receive power before there is any power available. Conventional flash-ROM however, needs power to be read. Thus, a new concept variation needs to be worked out.