Low-power sensor signal monitoring and impulse radio architecture for biomedical applications

Remote diagnostics of the vital information of a patient and the initiation of necessary actions by the healthcare professionals have resulted in the development of wireless body area network (WBAN). With little to no maintenance, each sensor node within a WBAN must operate with less than 100 μW of power consumption. Impulse radio architecture can be utilized to achieve this goal. This paper reports a low-power transmitter unit consisting of a Data Generator Block, an Impulse Generator Block and a Buffer. The Data Generator Block converts any electrochemical sensor current ranging from 0.2 to 2 μA to digital data. This block consumes a power in the range of 2.575–4.29 μW. The Impulse Generator Block utilizes an RC network to generate impulses of approximately 55 ns duration. Both the Data Generator Block and the Impulse Generator Block can operate with a 1 V supply. Finally, a Buffer circuit, which operates with a 2 V supply, is used to drive a standard 50 Ω load such as an external antenna. The peak current consumption of the impulses is 2.11 mA with a peak output voltage of 72 mV, making it extremely suitable for short range wireless communication. The entire system has been designed and fabricated using a 90 nm standard CMOS process. The average power consumption of the system is only 22.10 μW.