DC switching power supply for sapphire (Al2O3) single-crystal furnace is a DC switching power supply which is specially designed for single-crystal furnaces adopting Czochralski & Kyropoulos method in the growing of sapphire, as a DC voltage-regulating control power supply, it adopts DSP and CPLD as the control core, IGBT as the power inverting device and a high-frequency ultracrystalline transformer as the load-matching transformer. Adopting Schottky diode full-wave rectification, it realizes continuously adjustable output power by the phase controlled regulation way. In the entire inverting work process, by adopting high-precision power closed-loop control and LCC quasi-resonant mode, it realizes IGBT soft switching and reduces the switching losses of IGBT as well as the electromagnetic emission and conducted interference generated by the power supply to the outside world, what’s more, its multiple given signal selection functions and isolated conversion & output of output DC voltag