U.S. Philips Corporation

Lumileds Lighting B.v.

Engbert B Nijhof

Marcel J Bucks

Johannes E Algra

Johannes W Coenders

Stefan E Roijers

Johannes C Van Loon

Pieter W Habing

John E De Clercq

A circuit arrangement for operating a semiconductor light source includes connection terminals for connecting a control unit, an input filter, a converter comprising a control circuit, output terminals for connecting the semiconductor light source, an apparatus CM for removing a leakage current occurring in the control unit in the non-conducting state, and a self-regulating circuit for deactivating the apparatus CM. The circuit arrangement is also provided with a detection circuit for detecting an incorrect functioning of the converter or the semiconductor light source. For this purpose, preferably a minimum voltage and a maximum voltage are detected at the output terminals.

Circuit arrangement and signalling light provided with the circuit

A circuit for operation of a semiconductor light source having terminals for connecting a source of power and output terminals for connecting the semiconductor light source. The circuit is also provided with a controlled current generator and is also concerned with a signal head incorporating the circuit. The controlled current generator is controlled by the current flow through the semiconductor light source and the current supplied by the controlled current generator.

Controlled current generator for operating light emitting diodes

A circuit arrangement for operating a semiconductor light source, includes input terminals for connecting a supply voltage, an input filter, a converter having a control circuit, and output terminals for connecting the semiconductor light source. The circuit arrangement is provided with a voltage detector for detecting the output voltage at the output terminals.

Circuit arrangement, and signaling light provided with the circuit

A circuit arrangement for driving a light source includes input terminals (T1, T2) for deriving a supply current from a supply source; a circuit I for generating a control signal S; a circuit II, provided with a converter which is fitted with at least one switching element (13) and with a control circuit (17) which triggers the switching element with high frequency in a manner which is dependent on the value of the control signal S; a circuit III for generating a voltage Sc which is a measure for an instantaneous value of a supply voltage delivered by the supply source, the voltage Sc acting as a reference signal which causes the circuit I to generate a control signal S which lies alternately in a first range and in a second range, and the circuit II causing the drawing of a comparatively strong supply current (Iv1) at a value of the control signal S which lies in the first range, and the drawing of a comparatively weak supply current (Iv2) at a value of the control signal S which lies in the second range; and output terminals (T3, T4) coupled to the circuit II for connection to a light source (LI).

Circuit arrangement for controlling luminous flux produced by a light

In a multiresonant DC--DC converter provided with a switching element (S1), a transformer (T) and a rectifier coupled to the secondary winding (S) of the transformer, the rectifier is constructed as a diode bridge (D1, D2, D3, D4). It is achieved thereby that the maximum amplitude of the voltage across the switching element is comparatively low. The switching element is highly suitable for supplying a network of LEDs.

Circuit arrangement

A circuit arrangement for operating a semiconductor light source includes connection terminals for connection to a control unit, an input filter, a converter having a control circuit, and output terminals for connection to the semiconductor light source. The circuit arrangement is also provided with a self-regulating current-conducting network.

Circuit arrangement, and signalling light provided with the circuit

The apparatus comprises first and second input terminals (1, 3) for receiving an input voltage, a number of transformers (7), each of which comprises a primary winding (9) having first (13) and second (15) ends, and a secondary winding (11). At least one end of each primary winding is connected to a switching member (17) which comprises a first controllable switching element (19) and a second controllable switching element (21). This end (15) can be connected, via the first switching element (19), to the first input terminal (1) and, via the second switching element (21), to the second input terminal (3). The switching member (17) may be in a first state or a second state, the first switching element (19) being closed and the second switching element (21) being open in the first state whereas in the second state the first switching element is open and the second switching element is closed. The apparatus also comprises a control unit (31) for cyclically adjusting the various switching members (17) to the first and the second state at different instants.

Power supply apparatus

A digital device for controlling a three-phase motor comprises a circuit arrangement for generating three pulse-width modulated carrier waves which are 120.degree. phase-shifted relative to each other, whose modulation depth as a function of time represents a sinewave. A first clock signal periodically starts an up/down counter which counts the second clock signal. The carrier wave is generated by switching a flip-flop each time that the maximum count of the up/down counter is reached and the various modulation pulses which are required are generated symmetrically relative to this maximum count. A sequential network modulates the carrier wave sequentially with the correct modulation pulses.

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Eindhoven, Netherlands

Engbert B Nijhof