A power converter comprises an inductor coil whose first pole is connected to an input terminal of the power converter, a controllable switch between the ground and a second pole of the inductor coil, a first unidirectionally conductive component providing a path for electric current from the inductor coil towards an output terminal of the power converter when the controllable switch is non-conductive, and an over-current protector at the output terminal. The power converter comprises a second unidirectionally conductive component for conducting electric current from the input terminal to the over-current protector in a fault situation where voltage at the output terminal is smaller than voltage at the input terminal. Thus, the second unidirectionally conductive component constitutes a low-inductance bypass route for fault current and enables the over-current protector to react fast to a fault situation.