Abstract: A switched-mode converter produces a periodic square-wave signal whose amplitude depends on the input d.c. voltage. This signal is applied to an inductive network. A rectifier and a smoothing capacitor are coupled to this network with the output d.c. voltage being present across the capacitor. The frequency of the square-wave signal is controlled in dependence on the input voltage, namely so that it is directly proportional thereto or that the period decreases at a greater rate than the input voltage increases. A further control, for example, a series control, can be used to regulate the output voltage.