Power Management Unit for Solar Energy Harvester Assisted Batteryless Wireless Sensor Node.

This work describes an energy-efficient monolithic Power Management Unit (PMU) that includes a charge pump adapted to photovoltaic cells with the capability of charging a large supply capacitor and managing the stored energy efficiently to provide the required supply voltage and power to low energy consumption wireless sensor nodes such as RFID sensor tags. The proposed system starts-up self-sufficiently with a light source luminosity equal to or higher than 500 lux using only a 1.42 cm solar cell and integrating an energy monitor that gives the ability to supply autonomous sensor nodes with discontinuous operation modes.

A 21 m Operation Range RFID Tag for "Pick to Light" Applications with a Photovoltaic Harvester.

In this paper, a novel Radio-Frequency Identification (RFID) tag for "pick to light" applications is presented. The proposed tag architecture shows the implementation of a novel voltage limiter and a supply voltage (VDD) monitoring circuit to guarantee a correct operation between the tag and the reader for the "pick to light" application. The feasibility to power the tag with different photovoltaic cells is also analyzed, showing the influence of the illuminance level (lx), type of source light (fluorescent, LED or halogen) and type of photovoltaic cell (photodiode or solar cell) on the amount of harvested energy.

0.5 V and 0.43 pJ/bit Capacitive Sensor Interface for Passive Wireless Sensor Systems.

This paper presents an ultra low-power and low-voltage pulse-width modulation based ratiometric capacitive sensor interface. The interface was designed and fabricated in a standard 90 nm CMOS 1P9M technology. The measurements show an effective resolution of 10 bits using 0.