GaN power devices are an emerging technology that have only recently become available commercially. This new technology enables the design of converters at higher frequencies and efficiencies than those achievable with conventional Si devices. This paper reviews the characteristics and commercial status of both vertical and lateral GaN power devices, providing the background necessary to understand the significance of these recent developments. Additionally, the challenges encountered in GaN-based converter design are considered, such as the consequences of faster switching on gate driver design and board layout. Other issues include the unique reverse conduction behavior, dynamic Rds,on, breakdown mechanisms, thermal design, device availability, and reliability qualification. This review will help prepare the reader to effectively design GaN-based converters as these devices become increasingly available on a commercial scale.

In this paper, the far-field powering issues are addressed for low-power and low-duty cycle wireless sensors with low incident power density. Various technical details and design examples are examined in connection with low-power rectenna and power management system.

This paper presents a comprehensive short circuit ruggedness evaluation and numerical investigation of up-to-date commercial silicon carbide (SiC) MOSFETs. The short circuit capability of three types of commercial 1200 V SiC MOSFETs is tested under various conditions, with case temperatures from 25 o C to 200 o C and DC bus voltages from 400 V to 750 V. It is found that the commercial SiC MOSFETs can withstand short circuit current for only several microseconds with a DC bus voltage of 750 V and case temperature of 200 o C. The experimental short circuit behaviors are compared and analyzed through numerical thermal dynamic simulation. Specifically, an electro-thermal model is built to estimate the device internal temperature distribution, considering the temperature dependent thermal properties of SiC material. Based on the temperature information, a leakage current model is derived to calculate the main leakage current components (i.e. thermal, diffusion, and avalanche generation currents). Numerical results show that the short circuit failure mechanisms of SiC MOSFETs can be thermal generation current induced thermal runaway or high temperature related gate oxide damage.