Giulio Zoppi

An RF-powered FSK/ASK receiver for remotely controlled systems

A fully integrated RF-powered receiver for remotely controlled systems is presented. The receiver adopts ASK and FSK modulations and is capable of operating in the ISM bands of 433 MHz, 869 MHz, and 915 MHz, while achieving a bit rate down to 62 kb/s. The circuit includes an RF harvester and a power management unit for the RF to DC power conversion and control, respectively, and an OTP memory with a digital interface for the operating configuration. Measurements show a harvester sensitivity of -18.8 dBm and accurate ASK demodulation with a modulation index as low as 10%. The current consumption is 87 μA and 720 μA for the ASK and FSK receiving mode, respectively. The circuit was fabricated in a 0.13-μm CMOS technology and occupies a core area of 2.2 mm2.

An over-the-distance wireless battery charger based on RF energy harvesting

An RF powered receiver silicon IC (integrated circuit) for RF energy harvesting is presented as wireless battery charger. This includes an RF-to-DC energy converter specifically designed with a sensitivity of −18.8 dBm and an energy conversion efficiency of ∼45% at 900 MHz with a transmitting power of 0.5 W in free space. Experimental results concerned with remotely battery charging using a complete prototype working in realistic scenarios will be shown.

Sensors for Kinetic Energy Measurement Operating on “Zero-Current Standby”

The ever increasing need to extend battery life in IoT devices, self-powered sensors, and autonomous nodes highlights the need to reduce energy consumption as much as possible. One of the main issues still not fully addressed is the reduction of power consumption of sensors and measurement systems in standby mode, which represents a significant amount of the total power dissipation. In fact, nowadays, despite the continuous efforts, standby power is still far from being negligible. This paper exploits a new approach named “zero-current standby” to tackle this issue; moreover, due to the fact that the transducer implements kinetic-to-electrical energy conversion, a sensor that performs kinetic energy measurements is obtained and characterized. The proposed solution goes beyond the concept of the standby state itself, as it can actually be applied to appliances turned OFF. The design of a piezoelectric-based sensor able to measure kinetic energy is discussed in this paper. The proposed device will also allow zero-energy standby operation, with vibrations acting as trigger for sensor activation and data transmission via Wi-Fi. Numerical analysis, laboratory characterization, and experimental results of a complete working prototype are presented here, demonstrating both the suitability of the approach proposed and the improvement with respect to conventional strategies.

RF remotely-powered integrated system to nullify standby power consumption in electrical appliances

In order to increase energy efficiency in electrical appliances, autonomy in WSN (Wireless Sensor Network) nodes, IoT (Internet of Things) devices and self-powered sensors, it is necessary to reduce energy consumption as much as possible. One of the main issues to solve is reduction of standby power consumption, which is not negligible due to the enormous number of appliances involved. While in standby, power management circuits are permanently on, consuming unnecessary energy. This leads designers to consider power efficiency. In this article, a different approach is introduced based on Radio Frequency to electrical energy transduction with the intention to resolve this issue. The proposed solution goes beyond the well-known concept of standby as it instead applies to electric appliances that are off. An RF powered receiver silicon IC (integrated circuit) for remotely controlled systems is presented. This includes an RF-to-DC energy converter specifically designed with a sensitivity of -18.8dBm, which allows an operating distance of up 8 meters at 900 MHz with a transmitting power of 1Watt in free space. Experimental results using a complete working prototype will be shown.