Date: 15/12/2010

650V Silicon Carbide Schottky Diodes from Cree reduce diode losses in power supplies

Cree, Inc. has announced its new line of Z-Rec 650V Junction Barrier Schottky (JBS) diodes. The new JBS diodes provide blocking voltage to 650V to accommodate recent changes in data center power architecture that industry consultants estimate will result in energy efficiency gains of up to 5 percent.

As per Cree: Conventional switch-mode power supplies typically have an input voltage range of 90V - 264V, supporting various AC input sources worldwide. In existing data center power architectures, 3-phase/480V power is supplied from the local utility. This 3 phase/480V power is converted to 3 phase/208V by means of a power transformer and then further conditioned to provide input power to the server power supply. This conversion step reduces overall efficiency due to transformer losses.

Recent trends in data center power architecture call for the elimination of the 480V to 208V conversion to boost overall data center efficiency. Instead of providing 120V AC from the 3 phase/208V line to neutral, server power supplies will now be expected to accept a broader universal line voltage range of 90V - 305V (277V plus a 10 percent guard band) directly from the 3 phase/480V line to neutral. This architecture eliminates the need for the step-down power transformer, along with the related energy losses and expense, according to Cree.

Reverse recovery loss saving Schottky diodes that have an extended maximum blocking voltage of 650V are designed for power supplies used in servers, to cut power consumption significantly.

"Silicon carbide technology is critical to developing the next generation of advanced, energy-efficient data center power system designs because it virtually eliminates diode switching losses," explained Cengiz Balkas, Cree Vice President and General Manager, Power and RF. "Conventional silicon devices' switching losses are known to be big contributors to energy inefficiency, so replacing them with SiC devices can boost the efficiency of the power factor correction stage of the power supply by up to 2 percent, resulting in even greater overall efficiency improvement than with architectural changes alone."

The initial products in the 650V Z-Rec Schottky diode family, the C3DXX065A Series, include 4, 6, 8, and 10 amp versions in TO-220-2 packages. All devices are rated for operation from -55°C to +175°C.

The C3DXX065A Series devices are fully qualified and released for production use. For samples and more information about Cree's 650V Z-Rec devices or any of Cree's other 600V, 1200V and 1700V diodes.
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