Low power systems-on-chip for biomedical applications

This thesis describes the design and implementation of single-chip low-power biomedical Systems for a novel generation of medical devices. Mixed-signal systems-on-a-chip (SoC) have been designed for Operation and control in implanted ventricular assist pumps and for implanted blood pressure sensors. Finally, a specific market analysis has been performed prior to the development of a novel communication principle using the human body itself as a data bus. The first SoC described contains a 10 mW 2-channel eddy-current sensing device for 2D magnetic bearing control, which is part of a ventricular assist pump. Power consumption has been reduced by more than a factor of 15 and the accuracy of the position measure¬ ment has been improved from 8 to 10 bit through a new excite and readout concept. A micro-transponder has been designed for an implantedblood pres¬ sure sensor applying passive telemetry for batteryless Operation. Although it drives a low-ohmic sensor, the whole system includingdata acquisition and RF communication has been the first of its kind consuming less than 500 fiW. The last systemdecribes a novelcommunication approachwhich makes use of the dielectric characteristics of human tissue. Signals can be transmitted through the human body via galvanic coupling of AC currents in the \xA ränge. A simplified engineering model has been developed for the communication channel. The principle of Operation has been successfully tested with a digital ECG demonstrator.