In this paper we present a set of integrated circuits specifically designed for high temperature power applications such as isolated power transistor drivers and high efficiency power supplies.The XTR26010 is the key circuit for the isolated power gate drive application. The XTR26010 circuit has been designed with a high focus in offering a robust, reliable and efficient solution for driving a large variety of high-temperature, high-voltage, and high-efficiency power transistors (SiC, GaN, Si) existing in the market. The XTR40010 is used for isolated data communication between a microcontroller or a PWM controller and the power driver (XTR26010). The isolated power transistor driver features a dual turn-on channel, a turn-off channel and a Miller Clamp channel with more than 3A peak current drive strength for each channel. The dV/dt immunity between XTR26010 and XTR40010 exceeds 50kV/μs.To demonstrate the performance and reliability at system level, a half-bridge driver test-board has been developed for driving SiC MOSFETs. For supplying this test-board, a compact isolated flyback power supply with 82% power efficiency has been developed thanks to the versatile voltage mode PWM controller XTR30010 and the XT2N0825 N-Channel MOSFET.The full system including an isolated half-bridge gate driver and associated isolated power supply has been successfully tested up to 200°C, up to 600kHz of switching frequency and 600V high-voltage bus. The 200°C limitation is due to passives, PCB material, and the solder paste used for the test board. However, all used X-REL active circuits have been qualified within specifications well above 230°C.