STMicro Announces Silicon Carbide Schottky Diodes For Solar Power, Server Systems, & Motor Controllers
STMicroelectronics (ST) is introducing silicon carbide (SiC) diodes – the STPSC806D and STPSC1006D SiC Schottky diodes – which are described as being especially useful in converters for solar power systems, where every fractional efficiency percentage is valuable. The company claims that power supplies for servers and telecom systems, which are operational round the clock, will also benefit from the cumulative savings of this apparently small improvement in efficiency. These diodes can also be used in motor controllers.
According to ST, by saving the energy normally dissipated as heat by the silicon diode, the new 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.
A further benefit for switched-mode power supply (SMPS) designers is that SiC diodes such as the STPSC806D and STPS1006D allow higher switching frequencies, which enable other components such as filtering capacitors and inductors to become smaller and less expensive, and consume less power.
SiC technology is able to deliver these benefits because 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 current flowing during this recombination period is called the reverse recovery current. This undesired current, when combined with the voltage across associated semiconductor power switches, generates heat that will be dissipated by the switches. By eliminating this reverse recovery charge, SiC Schottky diodes have much lower switching losses across the board, leading to higher efficiency and lower heat dissipation.
The 8A-rated STPSC806D and 10A STPSC1006D, for 600V applications, are in full production in the industry-standard TO-220AC package, and available at $3.90 and $4.90, respectively, in quantities of 10,000.
