Abstract: A circuit for reducing peak current in dependence on line voltage in a blocking oscillator-switched power supply, includes a transformer having a primary winding and a control winding, an electronic switch connected in series with the primary winding, and a control circuit supplied by the control winding for controlling the electronic switch, the control circuit including a pulse processing stage addressed by rectified a-c line voltage fed into the primary winding, a start-up stage, and a variable voltage coupling stage coupling the pulse-processing stage to the start-up stage.

Abstract: A circuit for providing standby operation in a switched power supply with a blocking oscillator, includes a control circuit, an electronic switch driven by the control circuit, and a transformer having a primary winding connected in series with the electronic switch, a first secondary winding supplying power supply to a normal load of electrical equipment, a second secondary winding driving the control circuit, and a further transformer winding strongly coupled to the primary winding and loosely coupled to the first secondary winding for generating a control signal for a standby load supply.

Abstract: An improved blocking oscillator switched mode power supply, which is protected against a voltage rise on the primary side of a transformer of the switched mode power supply, which occurs in a no-load operation and could endanger the circuit. In a design of the blocking oscillator switched mode power supply according to the invention, the output of the variable gain amplifier, connected in known manner to an input of the pulse duration modulator (or pulse width modulator) of the control circuit of the blocking oscillator, is connected through an operational amplifier, which serves as comparator and is actuated by an auxiliary voltage to an additional input of the pulse duration modulator. The pulse duration modulator is provided in the usual manner for controlling the base of a switching transistor, forming a connection between one end of the primary side of the transformer and the terminal for the reference potential.

Abstract: A blocking oscillator converter with controlling logic system has an oscillator which, in the active state, blocks control of a switching transistor of the converter, and hence feeding of the electronic apparatus to be supplied by the converter. The oscillator blocks the output of a control circuit in the active state and, in the passive state, has no influence on the control of the switching transistor by the control circuit. The active state of the oscillator is triggered by monitoring of the possible operational errors by an error indicator when such an operational error occurs. After decay of the operational error has taken place, the oscillator again returns to the passive state. The advantage of the blocking oscillator converter with controlling logic system is primarily provided through a considerable reduction of the power dissipation in the blocking oscillator converter, and primarily in its switching transistor during error indications.

Abstract: Semiconductor circuit for supplying power to electrical equipment includes a control circuit with a first terminal for reference voltage connected, via a voltage divider formed of series connected resistances, to the anode of a diode; a second terminal for zero-crossing identification connected via a resistance to the cathode of the diode; a third terminal serving as an actual value input directly connected to a divider point of the voltage divider; a fourth terminal delivering a sawtooth voltage connected via a resistance to a terminal of a transformer primary winding; a fifth terminal serving as a protective input connected via a resistance to the cathode of another diode and, via two other resistances, to the cathode of a third diode having an anode connected to an input of a rectifier circuit; a sixth terminal for a reference potential connected via a capacitor to the fourth terminal and via another capacitor to the anode of the first-mentioned diode; a seventh terminal and an eighth terminal for respecti