Design Aspects and Environmental Impacts of Wide Band Gap based Semiconductor Technology in Chargers for Electronic Devices

Abstract

In recent years, Wide Band Gap (WBG) materials like silicon carbide (SiC) and gallium nitride (GaN) have increasingly become an alternative to standard silicon semicon ductors used in e.g., power converters. This paper is the outcome of selected work of Task B: “Energy and environmental related Life Cycle Assessment (LCA)”, of the Power Electronic Conversion Technology Annex (PECTA) of the Technology Collaboration Program Energy Efficient End-Use Equipment by the IEA (4E). This paper in particular focuses on chargers for electronic devices such as notebooks and mobile phones, and concentrates on two main areas: 1) The effects of incorporating GaN components for energy conversion on the product design; and 2) The resulting environmental impacts along the life cycle of the chargers. To answer these questions, the authors contacted experts from academia, research and industry to discuss the effects of WBG on the product design level. A functional structure of a power converter was used to describe the impact of using GaN transistors. A streamlined Life Cycle Assessment with the selected Climate change indicator Global Warming Potential (GWP) was completed for a conventional 65W Si-based laptop charger, taken as the reference product, and a novel 65W GaN-based multi charger. The inventory data for these chargers were obtained from power measurements carried out in PECTA (Task F), and their bills of materials (BOMs) were obtained from tearing down the two products. In general, the effect of using GaN on the design of the charger brings the possibility to increase the switching frequency, which enables size and weight reductions of components. Depending on pre-defined customer specification also a higher energy efficiency can be achieved (e.g., if Si or GaN transistors are utilizing the same operating frequency). In turn, both have repercussions on the environmental impact of the charger. For 500 to 1500 charging cycles the GWP due to WBG power semiconductor material also including the manufacturing phase (production of the WBG device itself) is compared with the reference Si-based charger. When the battery charger operates for 1500 charging cycles, the GWP of the materials and production of the WBG device must be lower than 3,50 kg CO2-eq. If the WBG charger would be used for only 500 charging cycles, the GWP of the materials and production of the WBG device should be lower than 1,64 kg CO2-eq. The results of this study show, that a reduction of environmental impacts over the entire life cycle may be possible through the use of WBG technology.