A device and method for charging a battery from a three-phase network, having a degraded charging mode, for example a battery of an electric traction automotive vehicle. The device includes a first filtering stage configured to be connected to the three-phase network, a voltage step-down stage connected to the filtering stage, a voltage step-up stage configured to be connected to the battery and coupled to the voltage step-down stage via an inductive component, a regulating unit configured to impose cyclic switching ratios on the voltage step-down stage and on the voltage step-up stage, and a device for comparing operating temperature of the regulating unit with a threshold value and controlling the charging based on two phases of the three-phase network when the operating temperature of the regulating unit exceeds the threshold value.