Raytheon UK’s Integrated Power Solutions  business unit in Glenrothes, Scotland, has developed a high-temperature, small-form-factor bridge leg power module. Aimed at high-speed switching applications, the module has potential uses in the aerospace sector as it requires minimal external cooling and presents considerable weight-saving opportunities within the More Electric Aircraft power system. Also, by supporting applications in harsh environments and in meeting high operating temperature demands, the module can also be used in the geothermal power and oil and gas sectors.

“The co-location of BJT base driver circuitry and power transistors into a single high-temperature module is a major industry breakthrough,” claims David Gordon, technical lead with Raytheon’s IPS. “For example, in many instances it is necessary to switch power-stage transistors at tens of kHz, and that requires getting the base driver circuitry as close as possible to the power transistors. However, in a high-temperature environment, that presents a problem,” he notes. “While silicon carbide transistors can switch high voltage and handle high temperatures, traditional silicon-based gate driver circuitry cannot cope with the heat. Silicon-on-insulator (SOI) raises the bar to about 220oC, but that’s still not high enough for some existing and emerging applications for power electronics. Raytheon’s HiTSiC CMOS circuitry on the other hand was designed to operate at 300oC, and has been tested at considerably higher temperatures.”

The module is packaged in a 32-pin hermetic dual in-line (DIL) ceramic package measuring about 40mm x 23mm.