SiC – from single crystal to reference design

Silicon carbide (SiC) is the basis for ever more efficient e-vehicles and charging infrastructures. onsemi offers a broad portfolio of SiC solutions and practical design support.

Silicon carbide SiC is increasingly becoming the driver of electrification in mobility. The wide-band-gap material is highly efficient at high voltages and is the basis of 800-volt drive systems. SiC is thus paving the way for lighter electric vehicles with greater range. It is also essential for achieving fast battery charging times comparable to filling up conventional vehicles. 

Comprehensive SiC portfolio

With demand for SiC on the rise, choosing the right supplier and partner is critical. onsemi offers a wide range of high-efficiency smart power solutions based on SiC under the name “EliteSiC”: the product range includes SiC diodes, SiC MOSFETs, SiC modules and silicon and SiC hybrid modules. The newest additions to the lineup are the 1700-V EliteSiC MOSFET and two 1700-V avalanche-capable EliteSiC Schottky diodes. The new 1700-V EliteSiC devices offer best-in-class efficiency with reduced power dissipation, exemplifying the high performance and quality standards of the EliteSiC family of products. 

End to End Manufacturing

But it is not only with its leading technology that onsemi meets the requirements of industrial power infrastructure and industrial drive suppliers – thanks to its end-to-end SiC manufacturing capabilities, users can also rely on a high level of supply security. onsemi’s supply chain begins with the growing of the single-crystal silicon carbide material at its plant in Hudson, New Hampshire. The entire manufacturing process is vertically integrated throughout. This is the basis for high quality, enables complete cost control and rapid scaling of the production footprint, as well as process optimization through rapid feedback throughout the value chain.

Practical design experience 

In addition, onsemi provides technical support from specialized automotive professionals and DC fast charging station design experts. Complete ecosystem design tools and detailed technical documentation of physical, scalable SPICE models provide customers with additional support at every stage of their design and development.

Example DC fast charging station

With the increasing spread of electric vehicles, the demand for DC fast chargers is also growing. But their design is often still uncharted territory for application, product or development engineers. To show them what the key design considerations are and how they should be addressed, onsemi EMEA’s systems engineering team has designed an example 25-kW DC fast charger based on SiC Power Integrated Modules (PIM). 

The charger has bidirectional capabilities, covers a wide output voltage range and is capable of charging 400 V and 800 V batteries. The input voltage is rated for EU 400-Vac and U.S. 480-Vac three-phase networks. The power stage delivers 25 kW over the voltage range of 500 V to 1000 V. Below 500 V, output current is limited to 50 A, reducing power in accordance with the profiles of DC charging standards such as CCS or CHAdeMO. Isolated CAN, USB and UART interfaces enable communication between power supply blocks, charging system controller, vehicle, service and maintenance. 

Overall, the design follows the guidelines of IEC-61851-1 and IEC-61851-23 standards for electric vehicle charging. Accordingly, the development process started with the definition of system requirements, went through feasibility studies, and finally led to a final design in several iterations. This included performance simulations using SPICE models and control simulations using MATLAB and Simulink. Based on the final design, concrete circuit diagrams, the layout of the printed circuit board and finally real prototypes were created. 

Know-how from practice for practice

Through the development of the DC fast charger, the onsemi team gained important insights into the interaction of the components and the development process. Customers of onsemi can benefit directly from this know-how – many design challenges can thus be mastered quickly and the new system can be brought to market in a significantly shorter development time.