Abstract: It is intended to improve especially a switched-mode power supply operating in accordance with the flyback converter principle, in such a manner that it has a characteristic during the run-up phase which is easier on the components compared with previously. To keep the regulating voltage of the regulating circuit (Rk) of the switched-mode power supply constant during the run-up phase, a differentiating capacitor (Cd) is connected in parallel with a diode circuit (D1) in one case and between the cathode terminals of two diode circuits (D1 and D2) in the other case. Keeping the regulating voltage constant results in a uniformly linear running-up of the switched-mode power supply output voltage (Ua), as a result of which lastly the loading on various components is also reduced.

Abstract: Method and circuit arrangement for generating a sinusoidal line AC voltage from a DC voltage. For generating a sinusoidal line AC voltage from a DC voltage, the DC voltage is converted into a square-wave voltage having voltage pulses whose durations are controlled in accordance with the variation of the sinusoidal line AC voltage to be generated. The square-wave voltage is transmitted via a high-frequency transformer. Subsequently, the transmitted voltage pulses are respectively tapped and filtered for a given chronological duration. A secondary side of the high-frequency transformer is respectively shorted during pulse pauses caused by the sinusoidal control of voltage pulse durations for a simultaneous constant applied pulse frequency. In these phases, energy is transmitted back to the source of the DC voltage via the high-frequency transformer. As a result, the circuit arrangement can also be employed as a charging circuit.

Abstract: Current-fed push-pull converter. In a current-fed push-pull converter that is composed of a step-down regulator and of a push-pull controlled transformer, the transformer is connected following the step-down regulator. The converter also has push-pull switches, a transformer unit and at least one DC voltage top circuit for a respective output DC voltage. The transformer unit is formed by an auto transformer.