Automotive-qual’d SiC diodes also suit smaller inverter designs

November 19, 2014 // By Graham Prophet
STMicroelectronics silicon-carbide (SiC) diodes suit the trend for inverters in smaller boxes everywhere, from PHEV battery chargers to solar generators; their increased surge-versus-normal current rating is well-suited, ST says, for Little Box Challenge designs

ST's automotive-qualified silicon-carbide (SiC) diodes are intended for advanced on-board battery chargers (OBCs) in electric vehicles such as Plug-in Hybrids (PHEVs) that demand high power-handing capability within a confined space.

These diodes allow designers to build smaller power modules; ST therefore also offers them as a choice for tackling the Little Box Challenge presented by Google and IEEE. ST is a device-manufacturer partner of this $1 million competition to design kW-scale inverters that are more than ten-times smaller than today’s inverters for various applications, particularly solar micro-generators.

The SiC diodes employ technology to prevent high-current spikes from damaging the device. Until now, designers have typically over-specified the diodes for safety, whereas ST’s new technology provides 2.5 times greater over-current capability versus rated current. This enables the use of lower-current diodes, which are smaller and more economical, without compromising reliability or losing efficiency.

ST’s SiC diodes are automotive qualified, and feature increased reverse-breakdown voltage of 650V, satisfying the voltage derating factors applied by designers and car manufacturers to ensure suitable safety margin between normal and short-term peak voltages across the semiconductors used in OBC.

The devices build on the known energy-efficiency advantages of SiC as a Wide Band-Gap (WBG) technology that enables lower switching losses and higher voltage ratings in relation to device size, compared to conventional silicon devices. These 650V devices include the 10A STPSC10H065DY in the TO-220AC power package and the 12A STPSC12H065DY in TO-220AC. In addition, the STPSC20H065CTY in TO-220AB package and STPSC20H065CWY in TO-247 are 2x10A dual-diode devices that help maximise space utilisation and reduce the weight of the OBC.

The parts are priced from $4.15 (100) for the STPSC10H065DY.