A low-power sensor read-out circuit with FSK telemetry for inductively-powered implant system

This paper presents a low-power sensor read-out circuit with FSK telemetry option. The proposed system consists of a data generator block and a FSK generator block. The data generator block converts a sensor current to a square wave data signal whereas the FSK generator block produces two different frequencies depending upon the value of the data signal. The relatively simple architecture of the proposed system facilitates the low-voltage and low-power operation. The system has been designed using AMI 0.5 mum CMOS process. Simulation results show that the proposed system can detect a sensor current in the range of 50 nA to 5 muA and the total power consumption is 431 muW with a 3.3 V supply. The circuit is ready to be submitted for monolithic integration.