Vishay, together with e-peas, is setting new standards in the IoT world. This is achieved by photovoltaic energy harvesting, among other factors, in conjunction with a hybrid supercapacitor. Energy harvesting is the retrieval of small amounts of energy from ambient energy sources, such as light, heat, vibration, or e-fields. The main energy-related challenges include effective harvesting, efficient transformation to a usable voltage level, and lossless storage.
Storage capacitors with minimum leakage current are key components here, and ENYCAP™ capacitor technology provides very good properties to satisfy this requirement. ENYCAP devices have small sizes, high energy density, low leakage current, and more than 90% of the rated capacitance, even after 35 000 deep discharge cycles. Such ambient energy sources — combined with the right conversion and charging technology — make sensors completely self-sustaining, allowing them to be used for considerably longer than the targeted 10 years for IoT applications. The goal of >10 years of usability can only be achieved if all components used are optimized in a nano-ampere design and operate efficiently with minimum losses.
The Vishay Harvester includes three tiny 7.5mm² silicon photocells with >13% efficiency, an ultra low power chip from a cooperation partner — which replaces discretely designed circuit parts like isolated back to back MOSFET switches for ultra low reverse current — and an optimized forward voltage diode that prevents the attached ENYCAP capacitor from discharging during dark periods. It also includes small, low core loss composite inductors for voltage conversion. The ultra low power chip even has an MPPT to maximize converted energy.
by Wind River