Substrate technology eliminates switching losses

STMicroelectronics has introduced silicon carbide (SiC) diodes that save energy normally lost during switching.

The STPSC806D and STPSC1006D SiC Schottky diodes are designed for use in converters for solar power systems and power supplies for servers and telecom systems, which are operational round the clock. The diodes can also be used in motor controllers. By saving the energy normally dissipated as heat by the silicon diode, the SiC technology enables engineers to consider a lower maximum current rating for the diode. This allows smaller components to be used without sacrificing usable power. In high power applications where heatsinks are normally used, these can also be made smaller leading to more compact power supplies delivering higher power density. No reverse recovery charge accumulates during the diode’s normal conduction period. When a conventional bipolar silicon diode is turned off, this charge must be dispelled by recombination between groups of charge carriers close to the diode junction. The unwanted current flowing during this recombination period - the reverse recovery current - when combined with the voltage across associated semiconductor power switches, generates heat that will be dissipated by the switches. By eliminating the reverse recovery charge, SiC Schottky diodes have low switching losses across the board resulting in lower heat dissipation.