Siemens Aktiengesellschaft

Mannesmann Aktiengesellschaft

Rudolf Schierjott

Harald Stasch

Bernhard Hering

Ernst Goepel

Gerhard Treffer

An illuminated sign is for traffic control, in particular for road traffic, and includes light sources for generation of the sign and a monitoring device for functional monitoring of the light source. The light sources are embodied as light diodes and the monitoring device is embodied as a device for the limited current loading of the light diodes. The functional monitoring of said sign can be achieved with reasonable technical requirements in both the deactivated and activated state thereof.

Illuminated sign for traffic control and method for functional monitoring of such a sign

Heating mechanism for warming the ink in the write head of an ink

A switch-mode power supply has a rectifier for producing a small d.c. voltage from an input a.c. voltage, and a converter which comprises a switching transistor and a transformer. The converter arrangement is a free-running conductive converter and the switching transistor is switched on in the currentless state.

Switch-mode power supply having a free-running forward converter

A circuit arragement for monitoring current in a switching converter, wherein an inductance is charged pulse-wise with a current via a power switch. In accordance with the invention, the mean value of the voltage drop across the inductance is formed via an RC-component and the power switch is blocked via a threshold value switch when a predetermined maximum voltage drop is exceeded across the inductance.

Current monitor for switching regulators

A switched power supply has a rectifier arrangement for generating a DC voltage from an input AC voltage. A converter arangement in the power supply has a switching transistor and a transformer. The converter arrangement is designed as a free-running flow converter, whereby the switching transistor is switched on in the current-free condition. A control stage with an electrically separated control loop is provided at the secondary side, whereby the control stage acquires the deviation of an output DC voltage from a prescribed value and sets the pulse duty factor for the switching transistor via the control loop.

Switched power supply comprising a free-running flow converter and

A secondary switch controller has an input circuit with an inductance and a semiconductor switch and an output circuit with a rectifier and a smoothing element. A circuit for controlling operation of the secondary switch includes an internal control loop responsive to the voltage at the inductance, an external control loop responsive to the output voltage, and a current limiting circuit responsive to the current flowing through the input circuit.

Secondary switch controller circuit for power supply

To increase the efficiency of a push-pull saturation converter, a choke is introduced in a common emitter circuit of switching transistors in the converter. In addition, a constriction may be provided in a center leg of a transformer core of a switching transformer within the converter. To further improve efficiency, an RC acceleration element may be provided in a base circuit for the switching transistors.

High efficiency push-pull saturation converter

The invention relates to an arrangement for interference suppression in electronic circuits. A system is disclosed for electromagnetically shielding electronic devices without mains separation at the input side and which generate high-frequency noise voltages, particularly converter circuits with shielded inputs and outputs electrically separated by transformers and which use filter circuits arranged at the input and output sides. A large-surface printed circuit having surface-wide electrodes on both surfaces is provided between the shielded circuit portion at the mains side and the shielded circuit portion at the output side of the circuit to be shielded. The one electrode of the printed circuit is connected to the shield at the mains side and its other electrode is connected to the device ground allocated to the shield at the output side.

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Munich, Germany

Rudolf Schierjott