DC switches using power electronics technology are increasingly used in dc power systems. Unlike other typical power electronic equipment, it is difficult for the DC switch to acquire energy from the primary circuit in the long-term closure state without d <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i</i> /d <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</i> or potential difference. As a result, the gate drivers of the devices in DC switches can only be powered from the ground via a complicated and expensive secondary isolation power supply system. This paper proposes a novel isolated gate driver power supply method based on thermoelectric generation for SiC DC switches. By utilizing the unique high operating temperature of wide-bandgap devices, self-power generation can be achieved through the temperature difference between the device and the environment even without d <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i</i> /d <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</i> or voltage difference. Following the comprehensive integration of the thermoelectric generator and the radiator, a 1.7kV/400A DC switch prototype capable of long-term steady self-power supply is developed, proving the efficacy of the proposed method.