DC-DC converter

Achieved is a DC-DC converter having a backflow protection function such that conduction loss is further suppressed. A DC-DC converter (1) is provided with: a voltage conversion unit (19) that steps down voltage applied to a first conduction path (15) and outputs the voltage to a second conduction path (16); a backflow state detection unit that detects the backflow state of current in the second conduction path (16); and a backflow protection control unit that performs a protective operation when a backflow occurs. A switching element (24) is provided in a third conduction path (18) disposed between the voltage conversion unit (19) and a reference conduction path (17). When a backflow state is detected, the backflow protection control unit operates to switch the switching element (24) to an OFF state. 以进步抑制导通损失的形式实现具备逆流保护功能的DCDC转换器。DCDC转换器(1)具备：电压变换部(19)，将施加于第导电路(15)的电压降压并向第二导电路(16)输出；逆流状态检测部，检测第二导电路(16)中的电流的逆流状态；以及逆流保护控制部，在逆流时进行保护动作。开关元件(24)设置于在电压变换部(19)与基准导电路(17)之间配置的第三导电路(18)，逆流保护控制部在检测到逆流状态的情况下，以将开关元件(24)