This paper describes the feasibility of integrating, high-temperature (HT) silicon-on-insulator (SOI) technology with silicon-carbide- (SiC-) based integrated circuits (ICs) to create an efficient, high-temperature (240 °C) power controller. A discussion of the use of HT SOI for high-level circuits (i.e., the microcontroller and the gate array) is provided along with an example circuit. Normally OFF JFETs made from SiC were used to drive the output loads. Issues and solutions for interfacing SiC JFETs with HT SOI technology are discussed. The use of a HT SOI MESFET is described as is a SiC-based JFET H-bridge circuit. Such circuit designs will improve the efficiency of future smart grid power controllers. Keywords: SOI, SiC, Power Controller, High Temperature, H-bridge, JFET, Smart Grid.