Abstract: Modern switching power supplies include an integrated component (IS) which effects the control of the switch (7). The component (IS) is often supplied with the necessary voltage (U.sub.V) in its inactive state via a protective resistor (14) and in its active state from a transformer winding (15). When a switch-off command is present at the component (IS), the switch (7) is not switched on; this has the effect that the component (IS) goes into a polling state during which it alternates between its inactive and its active state, the period being defined by the capacitance of the charge capacitor. In order to bring the component (IS) into its active state as soon as the switch-off command (U.sub.AB) has been taken away, the active state is blocked while the switch-off command is present. Accordingly, the capacitor (13) can immediately give off the supply voltage (U.sub.V) necessary for activation, as soon as the switch-off command (U.sub.AB) is withdrawn.

Abstract: The transformer of a blocking oscillator converter is magnetized in a flux phase during which a switch on its primary side is switched on. In a blocking phase, in which the switch is switched off, the transformer is demagnetized by giving off energy to a load connected on the secondary side. In order to ensure for the switch to be switched on only after the transformer is fully demagnetized, a transfomer voltage is formed and the switch is only allowed to switch on when the voltage of values with a polarity has returned to finite values with the opposite polarity. The threshold value begins at zero or a value of the first polarity after the switching power supply is put into operation and then shifts to values of a second polarity if the shift does not begin before the time at which the voltage at the load rises.

Abstract: A circuit configuration for a blocking oscillator converter switching power supply includes a switch. A transformer has a primary winding in the circuit of a direct voltage source being connected in series with the switch, and a secondary winding to be connected to a load. The transformer is magnetized in a first operating phase in which the switch is switched on and current flows in the primary winding, and is demagnetized in a second operating phase in which the switch is switched off and current flows in the secondary winding. An integratable control circuit has a demagnetization monitor detecting a voltage at a transformer winding and preventing the switched-off switch for being switched on until the feedback voltage in the blocking phase has exceeded a predetermined threshold value, and a suppression circuit blocking the turn-on enablement for the switch during a predetermined time after the beginning of the blocking phase.

Abstract: A circuit configuration for a fixed frequency blocking oscillator converter switching power supply includes an electric switch. A transformer has a primary winding connected in series with the electric switch in the circuit of a voltage source outputting a direct voltage with a first algebraic sign, the switch being alternatingly switched on in a first operating phase and switched off in a second operating phase, and a secondary winding having a voltage from which a rectified output voltage is attained. An integratable trigger circuit for pulse-width-modulated switching of the switch has an oscillator emitting a voltage oscillating periodically between upper and lower peak values, and a pulse width modulator connected between the oscillator and the switch for switching the switch as a function of the periodically oscillating oscillator voltage.

Abstract: When triggering a bipolar switching transistor the control current for switching on the bipolar switching transistor must be set properly. If the transistor is oversaturated, the switch-off time response is poor. With too low a control current, however, high forward losses occur. A method and circuit configuration for base current regulation of bipolar transistors in periodic switching operation is introduced. The method provides defining as a measure of the saturation of the switching transistor the base current time integral required for sweeping the base region of charge carriers, and setting as a function of this value the base current for switching on the switching transistor.

Abstract: A method and circuit for limiting the output current of a power supply with a self oscillating flyback converter, controls a primary peak current as a function of input and output voltages of the flyback converter. A quotient is formed from two given input variables and multiplied by a first constant. A second constant is added thereto and then multiplied by a third constant. The two input variables are defined by the input and output voltage of the flyback converter. The output voltage of the flyback converter is divided by the input voltage of the flyback converter in the quotient formation. The output variable is provided as a manipulated variable for controlling the primary peak current. The three constants are dimensioned for simulating a formal dependency existing in the flyback converter between the input and output voltages and the primary peak current of the flyback converter.