A DC-to-DC converter is an electronic circuit or electromechanical device which converts a source of direct current (DC) from one voltage level to another. It is a type of electric power converter. Power levels range from shallow (small batteries) to high (high-voltage power transmission).
This one of the electric car parts that converts higher-voltage DC power from the traction battery pack to the lower-voltage DC power needed to run vehicle accessories and recharge the auxiliary battery.