Ultra Low Power Event-Driven Sensor Interfaces

This paper reviews several examples of ultra low power sensor interfaces for IoT applications. In such applications, the sensing operation is often performed at a relatively low frequency, and sometimes it is heavily duty-cycled, or it should be triggered by particular events or thresholds. The paper reviews why dynamic sensor interface architectures are a good choice in this context, and gives several design examples that can operate dynamically and that can be triggered by a single clock pulse. Suitable ADC design strategies are explained, and two exemplary sensor interfaces are described: a capacitive sensor interface, and a resistor-based temperature sensor interface including analog correction techniques. Both designs are reviewed and the main features in terms of efficiency and performance are discussed.