A public lecture by Prof. Fortunato Dualibe of UMons, Belgium.

Abstract:

As the Internet of Things (IoT) evolves to become a ubiquitous technology, the development of its enabling technologies presents several challenges to circuit designers. Among them, the proper design of the short-range communication systems of the IoT sensor node, which must normally remain operable for weeks, months or even years supplied by a single battery or by means of energy harvesting (EH) techniques. Within the latter, Power Wireless Transmission (PWT) emerges as a suitable technique for powering battery-free sensors from RF energy available in the environment, as proven through numerous applications reported in the state-of-the-art literature. However, the amount of high frequency energy that can be collected is limited whereas the attainable voltage supply normally remains below 1 V. Therefore, designers must exploit ultra-low power (ULP) and ultra-low voltage (ULV ) design strategies in order to make the RF front-end operable under such constraints. This lecture presents the design of a ULP-ULV RF-powered CMOS front-end that can be used to interface low-rate autonomous sensors. A demonstrator was designed in a 65-nm CMOS technology and operates with a 0.5/0.6 V supply which is harvested from a 2.4 GHz RF signal. The main building blocks include the harvester, the voltage multiplier, the wake-up and power management unit, the OOK-modulated VCO, the class-E power amplifier and digital circuitry for reading an external sensor output and controlling the front-end operation.