STMicroelectronics of Geneva, Switzerland has unveilled a family of high-voltage silicon carbide (SiC) power MOSFET products, enabling power supply designers to drive up energy efficiency in applications such as solar inverters and electric vehicles, enterprise computing and industrial motor drives.
ST claims to be among the first firms to produce high-voltage SiC power MOSFETs, and has achieved what is said to be the industry’s highest temperature rating of 200°C. The properties of silicon carbide help to save at least 50% of the energy normally wasted passing through conventional silicon power transistors, it is reckoned. The devices can also be physically smaller for a high breakdown voltage. The technology is seen as essential for continued improvement in system energy efficiency, miniaturization and cost.
In computer rooms and data centers, high energy costs are driving power and efficiency to the top of many IT directors’ concerns, ST says. Replacing ordinary silicon switches with SiC devices in bulk power supplies helps to increase power usage effectiveness (PUE, a standard metric for determining data-center energy efficiency). The Climate Savers Computing Initiative (CSCI) claims that more energy-efficient networking systems and devices can help to save moe than $5bn and offset 38 million tons of CO2 by 2015.
SiC MOSFETs are also used in solar inverters, as an alternative for conventional high-voltage silicon insulated-gate bipolar transistors (IGBTs), to convert the DC output from the panel into high-voltage AC feeding into the mains supply with no special drive circuitry required. In addition, by operating at higher frequencies than IGBTs, SiC MOSFETs allow designers to miniaturize other components in the power supply, reducing the cost and size as well as enhancing energy efficiency.
In electric vehicles, SiC is expected to help to significantly increase the energy efficiency and reduce the size of traction systems. The US DRIVE Electrical & Electronics Technical Team (a partnership between industry and the US government’s Department of Energy) is calling for energy losses to be approximately halved by 2020 while also reducing size by more than 20%. Its roadmap specifies wide-bandgap semiconductors (such as SiC) as a focus for R&D to increase power-converter efficiency and make the device tolerate higher operating temperatures more safely. ST claims that the increased temperature capability of its SiC devices (200°C), compared with ordinary silicon and competitors’ SiC MOSFETs, will help to simplify vehicle cooling system design.
ST’s new SCT30N120 1200V SiC power MOSFET is currently sampling and will enter volume production by September. As well as the 200°C maximum operating temperature (reducing pc-board size, simplifies thermal management), features include:
typical on-state resistance (RDS(ON)) of 80mΩ at 25°C, and ≤100mΩ over the entire temperature range to 200°C; low turn-off energy and gate charge (ensuring efficient, high-speed switching); leakage current lower than 10μA typical (enhancing system energy efficiency and reliability, compared with other structures based on the same material); fast intrinsic and robust body diode (saving external freewheeling diode for cost/size reduction); and simplified gate drive circuitry (reducing costs of network driving).
The SCT30N120 is available in the firm’s proprietary HiP247 package, which has an industry-standard outline and is optimized for high thermal performance. The guide price is $35 in quantities of 1000 units.
