Wirelessly powered and bidirectional data exchanged in smart medical microsystems

This paper discusses innovative circuits and system techniques for building advanced smart medical devices (SMD). Since typical SMDs contain implantable parts, low power consumption and high reliability are among the main criteria that must be given priority when designing such wirelessly powered microsystems. In order to calibrate the total inductively transmitted power to an implant, a wireless feedback loop is used. In addition, this inductive link allows full-duplex high data-rate communication, accomplished with a differential hard-limited Costas loop. A typical device, for monitoring and microstimulating the cortical tissues, comprises several integrated modules assembled on a thin substrate, providing placement flexibility in the body. Experimental results from integrated circuits are presented.