Category: Power Product of the Year
The power conversion market has an insatiable demand for higher power density and efficiency, from lower static and dynamic losses along with more thermal and electrical design margin. This is all without compromising reliability or cost, in an ever-wider range of hard and soft switched applications. Silicon-based semiconductor switches have dominated the landscape of power conversion for decades, with IGBTs and Si MOSFETs providing mature, robust solutions. However, industry predictions estimate that over the next five years, the CAGR% of SiC will grow to 24-30% – compared to 6-8% (Global Mkt Insights) for older technologies. While initial adoption of SiC has been slow but steady due to perceptions about price and drop-in capabilities, the new generation of SiC technology is set to accelerate adoption to meet forecasts due to ease of integration, unmatched Figures of Merit (FoM), new levels of cost-effectiveness, and its ability to address key design concerns in high-power applications.
Launched in December 2020, these four devices are the only 750V SiC FETs currently available on the market and the first in the 4th generation of SiC FET devices. The ultra-low on-resistance per unit area allow standard discrete packages with performances not achievable with incumbent Si or emerging WBG competing technologies. As with UnitedSiC previous generations, Gen 4 combines a SiC JFET with a low voltage Si MOSFET as a ‘cascode’ in a single package, to form what they have dubbed a ‘SiC FET’, combining the speed and efficiency of WBG technology with the easy gate drive of a Si MOSFET.
Available in 18 and 60 mohm options, these SiC FETs deliver unmatched FoMs with reduced on-resistance per unit area and low intrinsic capacitance. In hard-switching applications, the Gen 4 FETs exhibit the lowest RDS(on) x EOSS (mohm-uJ) resulting in lower turn-on and turn-off loss. In soft-switching applications, their low RDS(on) x Coss(tr) (mohm-nF) specification provides lower conduction loss and higher frequency. These devices not only surpass existing competitive SiC MOSFET performance whether running cool (25˚C) or hot (125˚C), but also offer the lowest integral diode VF with excellent reverse recovery delivering low dead-time losses and increased efficiency.
In expanding UnitedSiC’s offering to 750V, the new devices offer crucial designer headroom and reduced design constraints. This higher VDS rating also makes these FETs beneficial for 400/500V bus voltage applications.
Gen 4 SiC FETs from UnitedSiC retain the major advantage that they can be safely driven from fully off to channel fully enhanced using a 0V-12V gate drive with a maximum of +/20V, clamped by integrated ESD protection diodes.
As with earlier SiC FET generations, the high maximum gate drive voltage allows parts to be retrofitted into existing circuits to change out IGBTs, Si-MOSFETs and SiC-MOSFETs with little or no modification to the gate drive arrangement, for an instant boost in performance. As a bonus, total gate charge of SiC FETs is a few tens of nanocoulombs, so that even when switched at high frequency, gate drive power required is minimal. Also, as in previous generations, Gen 4 SiC FETs have robust avalanche and short circuit ratings.
With figures of merit that excel in all areas and convenient, thermally enhanced packages, Gen 4 is set to enable new standards of efficiency and power density from chargers, rectifiers, PFC stages and DC-DC conversion in all power conversion and storage applications. In the midst of the current wave of green initiatives put in place by governments to drive the fast adoption of EV and renewable energy technologies – power efficiency will be paramount. This next generation of SiC will be a key driver in accelerating R&D and lowering the cost to the end-consumer by making green technology far more efficient.
Technical overview: https://www.youtube.com/watch?v=fjAhyhY3lT4&feature=youtu.be