An 8-mode reconfigurable sensor-independent readout circuit for trillion sensors era

The Internet of Things (IoT) is opening the doors to many new devices and applications. Such an increase in the variety of applications requires reconfigurable, flexible and expandable hardware for fabrication and development cost reduction. This has been achieved for the digital part with devices like Arduino. However, the sensor readout Analog-Front-End (AFE) circuits are mainly designed for a specific sensor type or application. Such an approach would be feasible for the current small number of applications and sensors used. However, it will increase cost drastically as the variety and number of applications and sensors are increased. Moreover, flexibility and expandability of the system will be limited. Therefore, a universal sensor platform that can be reconfigured to adapt to various sensors and applications is needed. Moreover, an array of such circuit can be made with the same sensor to increase measurement accuracy and reliability. It can also be used to integrate heterogeneous sensors for increasing the flexibility of the system, which will make the system adaptable to many applications through only activating the desired sensors. In this paper, an 8-mode reconfigurable sensor readout AFE with offset-cancellation-resolution enhancing scheme is proposed to serve as a step towards a universal sensor interface. The proposed AFE can be reconfigured to interface resistive, capacitive, current producing, and voltage producing sensors through direct or capacitive connection to its terminals. The proposed system is fabricated in 180nm CMOS process and has successfully measured the four types of sensor outputs. It has also been interfaced to Arduino board to allow easy interfacing of various sensors. Therefore, the proposed work can be used as general purpose AFE resulting in manufacturing and development cost reduction and increased flexibility and expandability.