Versatile SiC JFETs Benefit Power Switching And Circuit Protection Applications
Written by by Peter Losee and Anup Bhalla, UnitedSiC, Monmouth Junction, N.J.
After more than two decades of promise, SiC switch technology has finally emerged as a contender for various power electronics applications, driven largely by adoption in automotive and industrial charging sectors, energy storage, PV inverters and even EV drivetrain inverters. Continued advancement in cost-performance metrics of SiC switches have even yielded inroads in growing volume applications such as telecom rectifier and server power supply applications, where silicon superjunction FETs have reigned supreme.
Although most of the major players in the power semiconductor world have focused their attention on SiC MOSFETs, the case can be made that the SiC JFET is the highest performance and most versatile switch technology available. In this article, we examine some of the unique attributes of SiC JFETs that are so attractive across a variety of potential applications.
After reviewing the key characteristics of SiC JFETs, we describe their performance advantages when applied in cascode configurations and used with particular power supply topologies and switching schemes. An extension of the single-JFET cascode, the “supercascode” combines a low-voltage silicon MOSFET with multiple series-connected SiC JFETs. The supercascode devices offer higher performance alternatives to silicon IGBTs and thyristors in medium voltage (6.5 kV to 10 kV+) and high voltage (tens of kilovolts and higher) power switching applications. Finally, we discuss how the low on-resistance and robustness of SiC JFETs provide performance advantages in power switching and circuit protection applications.