16 May 2016

ST unveils 650V and 1200V SiC power devices for EV applications

STMicroelectronics of Geneva, Switzerland has announced high-efficiency silicon carbide (SiC) power semiconductors for hybrid and electric vehicles (EVs), with a timetable for qualification to the automotive quality standard AEC-Q101.

ST says that, in EVs and hybrids (where better electrical efficiency means greater mileage), its latest SiC technology enables auto makers to create vehicles that travel further, recharge faster, and fit better into owners' lives. The firm is among the first to present new-generation rectifiers and MOSFETs for high-voltage power modules and discrete solutions addressing all the vehicle's main electrical blocks. These include the traction inverter, on-board battery charger, and auxiliary DC-DC converter.

Existing power modules typically rely on standard silicon diodes and insulated-gate bipolar transistors (IGBTs). As a wide-bandgap technology, SiC allows smaller device geometries capable of operating well above the 400V range of today's electric and hybrid drivetrains. The smaller SiC diode and transistor structures present lower internal resistance and respond more quickly than standard silicon devices, which minimizes energy losses and allows associated components to be smaller, saving even more size and weight.

"Major carmakers and automotive tier-1s are now committing to silicon carbide technology for future product development to leverage its higher aggregate efficiency compared to standard silicon in a wide range of operating scenarios," says Mario Aleo, group VP & general manager, Power Transistor Division. "Our SiC devices have demonstrated superior performance and reached an advanced stage of qualification as we support customers preparing to launch new products in the 2017 timeframe," he adds. 

ST has been among the first firms to produce SiC high-voltage MOSFETs, with its first 1200V SiC MOSFET introduced back in 2014, achieving a 200°C rating for more efficient and simplified designs.

The firm is fabricating SiC MOSFETs and diodes on 4-inch wafers. But, to drive down the manufacturing costs, improve the quality, and deliver the large volumes demanded by the auto industry, ST is scaling up its production of SiC MOSFETs and diodes to 6-inch wafers, and is on schedule to complete both conversions by the end of 2016.

ST has already qualified its 650V SiC diodes to the AEC-Q101 standard, and will complete qualification of the latest 650V SiC MOSFETs and 1200V SiC diodes in early 2017. The qualification of the new-generation 1200V SiC MOSFETs will be completed by the end of 2017.

The STPSC20065WY 650V SiC diode is in full production now in DO-247. The range also includes lower current ratings and smaller-form-factor TO-220 package options. The STPSC10H12D 1200V SiC diode is sampling now to lead customers in the TO-220AC package and goes into production in May, with volume production of the automotive-grade version planned for fourth-quarter 2016. Multiple current ratings from 6A to 20A and packaging options will also be available.

The SCTW100N65G2AG 650V SiC MOSFET is sampling now to lead customers in the HiP247 package, and will ramp up in volumes in first-half 2017. To enable more compact designs, a 650V SiC MOSFET in the surface-mount H2PAK will also be qualified to AEC-Q101 in first-half 2017.

Using the 650V SCTW100N65G2AG SiC MOSFET in the EV/HEV main inverter (typical frequencies up to 20kHz) increases the efficiency compared with an equivalent IGBT solution by up to 3%, the firm claims. This improvement translates into longer battery life and autonomy, and a smaller and lighter power unit with lower cooling requirements. The SiC MOSFET reduces power losses in the inverter (up to 80% lower at light/medium load), enabling designers to use higher switching frequencies for more compact designs. Additionally, a SiC-based solution offers highly robust intrinsic-body diodes, eliminating the need for the freewheeling diodes necessary with IGBTs, further saving cost, size, and weight, adds ST.

In other EV/HEV applications like the OBC (on-board charger) and DC-DC converter, the inherently faster switching performance of SiC, compared with standard silicon devices, allows much higher switching frequencies, reducing the size of passive components. Furthermore, the SiC MOSFET increases design flexibility as it can be used in diverse topologies, says the firm.

Such advances are helping to propel the state of the art in hybrid and electric vehicles, says ST. The firm claims that its manufacturing processes deliver advantages over competing SiC devices, such as superior stability over a wide operating temperature range, translating to more dependable vehicle performance and range.

Housed in a proprietary high-thermal-efficiency HiP247 package, ST's SiC MOSFETs also feature what is claimed to be the industry's highest junction temperature rating of 200°C and show very small variation in on-state resistance even at high temperatures. This leads to higher system efficiency, which reduces cooling requirements and PCB form factors, simplifying thermal management, says the firm.

The new 650V and 1200V SiC diodes have what is claimed to be the best-in-class forward voltage drop (VF) of all devices on the market, minimizing the energy dissipated as heat by EV/HEV power converters. These thermal properties help to further improve overall vehicle reliability, the firm adds.

See related items:

ST launches automotive-qualified 650V SiC diodes, targeting on-board battery chargers and Little Box Challenge

Tags: STMicroelectronics SiC power devices

Visit: www.st.com/sic-auto-diodes