Patent-treuhand-gesellschaft F. Elektrische Gluehlampen Mbh

Patent-treuhand-gesellschaft Fuer Elektrische Gluehlampen Mbh

Osram Gmbh

Osram Ag

Michael Boenigk

Klaus Guenther

Hans-Georg Kloss

Andreas Huber

Guenther Hirschmann

Franz Bernitz

Dirk Grundmann

Marc Czichy

Andreas Naujoks

Teja Tehmann

Matthias Lau

Teja Lehmann

Melanie Roth

In an embodiment a light emitting device includes a light source, a switching element having an input capacitance associated therewith, the switching element being configured to control a current flow to the light source in accordance with a charging of the input capacitance, a voltage control element coupled with the switching element and having a voltage supply node, the voltage control element having a second capacitance associated therewith, wherein the voltage control element and an input of the switching element are coupled to one another such that the voltage control element and the input of the switching element form a capacitive voltage divider and a driving element configured to provide a driving voltage at the voltage supply node, the driving voltage being greater than a maximum allowable input voltage of the switching element, wherein a relationship between the input capacitance and the second capacitance is in accordance with a relationship between the driving voltage and the maximum allowable input voltage.

Light emitting device

The invention relates to a high-pressure discharge lamp having a discharge vessel () sealed at both ends, a filling which can be ionized and is enclosed in the discharge area () of the discharge vessel (), and electrodes () which extend into the discharge area (), in order to produce a gas discharge, with the discharge vessel () having an electrically conductive coating () which is designed as a starting aid and is arranged at least in the boundary area () between the discharge area () and a first sealed end () of the discharge vessel ().

High-pressure discharge lamp

A high-pressure discharge lamp has integrated in its base or base housing a circuit arrangement (SCH) which combines a starting device and a power reducing circuit which comprises a phase-gating control (PS). A capacitor (C,) connected in parallel with the lamp (L) provides a transfer voltage which is distinctly higher than the input voltage of the arrangement.

Circuit arrangement, an assigned electrical system and a discharge lamp with such a circuit arrangement, and a method for operating it

A circuit arrangement for starting and for operating high-pressure lamps makes an increased transfer voltage available to the discharge lamp. The increased transfer voltage is generated by voltage doubling across a rectifier unit by means of a charging capacitor (LK), separated into two individual capacitors (C,C,), the common midpoint (M) of the capacitors (C,C,) being connected to the two network inputs of the rectifier unit.

Circuit arrangement for starting and for operating high-pressure lamps

To provide for effective control of a discharge lamp, typically, a sodium gh pressure discharge lamp, which operates in two phases, namely, a power pulse phase, followed by a holding phase, without extensive and complex electronic circuitry, two individual oscillator systems are provided, one for each phase; the oscillator systems include a first power burst oscillator formed as a first half bridge by two transistors (T1, T2), and an individual connecting current limiting inductance (L1) to the lamp (E), and a second oscillator including a two-transistor second half bridge (T3, T4) and an individual current limiting inductance (L2) coupled to the lamp. The respective oscillators are controlled, in a closed control loop, by a burst generator (BG) and a holding pulse generator (SG), each of which provide their signals to a logic circuit (LK) which provides for exclusive control of the respective first or second half bridge. A lamp voltage sensing circuit (C4, R2) taps lamp operating voltage, which is compared with a command signal to control through a repetition frequency control generator (WG), the recurrence rate of the bursts from the power bursts generator (BG). The lamp starting circuit (4) can also be controlled from the sensed signal by comparison with a reference in a second comparator (K) and suitably applied to an ignition circuit by an ignition monitoring logic. A pair of electrolytic capacitors of essentially the same value is connected across the d-c supply and their midjunction to the lamp.

Discharge lamp typically a sodium high-pressure discharge lamp, from an

To control the color temperature of a sodium high-pressure discharge lamp, preferably having a sodium and xenon fill, which may also include mercury, without essentially affecting the color rendition index of the emitted light, or the light flux or intensity of light radiation emitted, the lamp is operated under pulsed conditions, in which the instantaneous pulse power of recurring power pulses, separated by a holding phase to prevent extinction of the lamp, is controlled. Preferably, the overall energy of any one of said power pulses and the intervening holding pulse is maintained essentially constant, for example by varying the frequency of sub-pulses or oscillations of which the sequential power pulses are constituted. A frequency and power controllable oscillator (1) is connected to the lamp (3) through a series LC network to effect such control, thereby permitting adjustment of color temperature and matching of the light output to selective color reflectivity of illuminated objects.

Method of controlling the color temperature in a sodium high-pressure

To provide for optimum control of a sodium high-pressure discharge lamp operating under saturated operating conditions, such that the lamp will be operating stably and providing light output which is an optimum with respect to the color rendition index (Ra), light output or luminous flux, and color temperature, without regard to manufacturing tolerances or variations in power supply voltage, the energy supplied to the lamp is controlled with respect to a quotient formed of lamp voltage and lamp current (V.sub.L /I.sub.L), said quotient being determined with respect to optimum light values. The power supply for the lamp (3) either is a stabilized output voltage power supply (22) in which the output current is controlled, or an oscillator (32) providing bursts or power pulses (10, 10') formed of oscillations (11). Both the number of power pulses as well as holding pulses (12) between power pulses (to prevent extinction of the lamp), energy level of the respective pulses and frequency of oscillations, respectively, can be controlled to obtain the optimum value for the quotient of lamp voltage and lamp current.

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Berlin, Germany

Michael Boenigk