Silicon Carbide Footprint Growing in Power Electronics

The SiC semiconductors showcased at this year's PCIM in Nuremberg demonstrate their readiness for industrial, automotive, and energy applications.

Silicon carbide (SiC) offerings—and their advantages like higher efficiency, greater power density, smaller footprint and lower cost—were all the rage at this year's PCIM show held May 16th to 18th in Nuremberg, Germany.

ON Semi, for instance, came to the show with two SiC diodes: the 650 V FFSP3065A and the 1200 V FFSP20120A. Then, there was Infineon, which unveiled the Easy 1B SiC module during the PCIM 2016 show; the company announced that it's now starting the volume production of the Easy 1B modules.

The Easy 1B module is suitable for industrial drive, solar and welding applications. Image courtesy of Infineon.

"Silicon carbide has reached a tipping point," said Peter Wawer, division president of Industrial Power Control at Infineon Technologies.

The German chipmaker also showcased the 1200 V CoolSiC™ MOSFETs that boast dynamic losses an order of magnitude lower than 1200 V silicon IGBTs. And Infineon claims that these SiC MOSFETs feature very fast switching transients.

Moreover, with a threshold voltage (V th ) of 4 V and the recommended switch-on threshold (V GS ) of +15 V, the SiC transistors can be controlled like an IGBT and safely switched off in the event of a fault.

These SiC MOSFETs are initially being targeted at cost-sensitive applications such as photovoltaic inverters, UPS (uninterruptible power supply), and charging and storage systems. Eventually, Infineon sees their application being used in industrial drives and auxiliary power supplies in the railway systems.

It's probably not a coincidence that STMicro's new SiC diodes are also aiming at cost-conscious designs like solar inverters, home appliances, and power adapters. And, like Infineon, ST is also eyeing more performance-oriented use cases that mandate superior efficiency, low weight, small size, and more robust thermal properties.

Take, for instance, onboard battery chargers (OBC) and charging stations for electric and plug-in hybrid vehicles. The low forward voltage (V F ) of ST's 1200 V SiC diodes provides designers with leverage to achieve high efficiency and reliability by using power chips with the lower current rating, thus reducing the overall cost.

ST's 1200 V SiC diodes cover current ratings from 2 A to 40 A.
The products with large current ratings—like power modules—are required to suppress the effects of surge voltage during switching in order to maximize the high-speed switching characteristics of SiC.
That's why Rohm claims to have developed a new package for its SiC modules for better managing current ratings that range from 100 A to 600 A.

Rohm, which mass produced the first SiC power module back in March 2012, has launched two 1200 V SiC modules that are rated at 400 A and 600 A and are optimized for inverters and converters in solar power conditioners, UPS, and power supplies for industrial equipment.

The circuit diagram of Rohm's SiC module, which integrates Schottky barrier diodes (SBDs) and MOSFETs, making possible high-frequency operation above 100 kHz. Image courtesy of Rohm.

And like Infineon's SiC power modules, Rohm's new offerings claim a reduction in the switching losses compared to IGBT modules of the same current ranging. However, unlike Infineon, Rohm has quoted a figure: 64% at a chip temperature of 150°C. That, according to Rohm, allows the miniaturization of cooling systems.