Abstract: The present invention relates to an electronic ballast for discharge lamps (LA) which have preheatable electrodes (E1, E2). The electronic ballast has a measuring apparatus (M), which is designed to measure, during the preheating process, a variable, which is correlated with the electrode temperature increased by the preheating, of at least one of the electrodes (E1, E2) of a connected discharge lamp (LA), and a control apparatus (C), which is designed to match the electrode temperature, during the preheating process, in response to the measurement by adjusting an operational parameter of the electronic ballast. Furthermore, the electronic ballast is designed to detect cross discharges or a sufficient operating temperature of one of the electrodes (E1, E2) and possibly to ignite the discharge.

Abstract: A circuit arrangement for operating a low-pressure gas discharge lamp with a first and a second filament, between which a gas discharge can be formed, is provided. The circuit arrangement may include a device for generating an electrical potential which varies over time at a node, which is connected to the first filament via a first inductive element, and a half-circuit, which includes a switch, the first filament being electrically connected to the second filament when the switch of the half-circuit is closed, wherein a second inductive element is provided in the half-circuit.

Abstract: A circuit arrangement for striking a discharge lamp, comprising: a drive apparatus, having an output adapted to provide a drive signal with a predeterminable frequency; an inverter, which is coupled to the output of the drive apparatus, and having an output adapted to provide a square-wave signal with a predeterminable duty factor; a load circuit, which is coupled to the output of the inverter and has at least one terminal for the discharge lamp, the load circuit comprising a lamp inductor, which is coupled in series between the output of the inverter and the at least one terminal for the discharge lamp; a first control loop with a first reference variable, a first manipulated variable and a first controlled variable, the first control loop having a first time constant; a second control loop with a second reference variable, an auxiliary manipulated variable and a second controlled variable, the second control loop having a second time constant; and a strike detection apparatus, which is adapted to detect str

Abstract: An electronic ballast for an electrical lamp (2) provided with a first (21) and a second filament (22), includes a heating device which is used to heat the filaments (21, 22) and includes a resonance circuit (5), and an evaluation unit (11) designed for the evaluation of at least one measuring value of an electrical parameter during pre-determinable adjustments of operating conditions of the resonance circuit (5). The number of filaments (21, 22) of the electrical lamp (2) in electrical contact with the electronic ballast (1) can be identified according to the measuring value, and the electrical lamp (2) can be switched on by the electronic ballast (1) according to the identified number. A method for operating an electrical lamp by an electronic ballast is also described.

Abstract: The present invention relates to a circuit arrangement for operating at least one lamp (LA), which has a first filament (W1) and a second filament (W2), it comprising an apparatus (10) for determining a variable which is correlated with the temperature of at least one of the two filaments (W1; W2). It also relates to a method for operating at least one lamp, which has a first and second filament, a variable correlated with the temperature of at least one of the two filaments being determined prior to restarting the lamp.

Abstract: The present invention relates to a circuit arrangement for operating at least one electric lamp (LP) having a drive circuit (16), which has at least one terminal for a system voltage (UN) on the input side and at least one terminal for the at least one electric lamp (LP) on the output side; the drive circuit (16) having a control unit (18) and a step-up converter having a step-up converter inductor (L2) and a switch (S1), and the control unit (18) being designed to operate the step-up converter in a discontinuous mode, in which the current (IN) through the step-up converter inductor (L2) has gaps, the duration (?t) of these gaps being varied. It also relates to an operating method for at least one electric lamp (LP) using such a circuit arrangement.

Abstract: The present invention relates to an electronic ballast for discharge lamps, for example low-pressure discharge lamps, having a converter having a switching element and a two-part lamp inductor which is connected upstream and downstream of the discharge lamp. An electronic ballast according to the invention has a smoothing circuit which reduces voltage jumps caused by switching operations in the converter at the lamp terminals.

Abstract: The present invention relates to a circuit arrangement for operating at least one electric lamp and at least one LED including: an inverter having a bridge circuit having at least one first bridge transistor and one second bridge transistor arranged in series with one another, a center point of the bridge circuit being defined between the first and second bridge transistors; a lamp supply unit for supplying the electric lamp with energy from the bridge circuit, which includes a supply line with an inductance, via which the center point (M) of the bridge circuit is coupled to a first connection for the electric lamp; the lamp supply unit including an LED supply unit, which is designed to supply the at least one LED with energy. Moreover, it relates to an operating method for at least one electric lamp and at least one LED using such a circuit arrangement.

Abstract: The present invention relates to a circuit arrangement for operating at least one electric lamp (LP) having a drive circuit (16), which has at least one terminal for a system voltage (UN) on the input side and at least one terminal for the at least one electric lamp (LP) on the output side; the drive circuit (16) having a control unit (18) and a step-up converter having a step-up converter inductor (L2) and a switch (S1), and the control unit (18) being designed to operate the step-up converter in a discontinuous mode, in which the current (IN) through the step-up converter inductor (L2) has gaps, the duration (?t) of these gaps being varied. It also relates to an operating method for at least one electric lamp (LP) using such a circuit arrangement.

Abstract: A circuit arrangement for operating at least one LED and at least one electric lamp having at least one first filament and one second filament, includes first and second terminals for the corresponding filaments; and a lamp supply unit supplying power to the electric lamp; it also including an LED supply unit coupled to the second terminal for the second filament of the electric lamp and designed to supply power to the at least one LED. Also described is an operating method for the circuit arrangement operating at least one LED and at least one electric lamp as described. The circuit arrangement also includes an LED supply unit, which is coupled to the second terminal for the second filament of the electric lamp and supplies power to the at least one LED.

Abstract: The invention relates to a converter circuit with coupled inductances L1 and L2 which have a core K having an air gap S which is asymmetrical with respect to the inductances.

Abstract: The present invention relates to an electronic ballast for discharge lamps, for example low-pressure discharge lamps, having a converter having a switching element and a two-part lamp inductor which is connected upstream and downstream of the discharge lamp. An electronic ballast according to the invention has a smoothing circuit which reduces voltage jumps caused by switching operations in the converter at the lamp terminals.

Abstract: The present invention relates to a circuit arrangement for operating at least one lamp (LA), which has a first filament (W1) and a second filament (W2), it comprising an apparatus (10) for determining a variable which is correlated with the temperature of at least one of the two filaments (W1; W2). It also relates to a method for operating at least one lamp, which has a first and a second filament, a variable correlated with the temperature of at least one of the two filaments being determined prior to restarting the lamp.

Abstract: The invention relates to a converter circuit with coupled inductances L1 and L2 which have a core K having an air gap S which is asymmetrical with respect to the inductances.

Abstract: The invention relates to an electronic ballast for lamps with a regulation of the lamp current ILi. In this case, the intermediate circuit voltage UZi is taken into account by a disturbance variable application SG.

Abstract: The invention relates to an operating circuit for a discharge lamp with a current regulation circuit for regulating the lamp current and a detection circuit for identifying proximity to capacitive operation of the load circuit. The operating circuit is designed to reduce the nominal current value on identifying proximity to capacitive operation.

Abstract: The invention intends to improve the determination of the resonant frequency of a resonant circuit, in particular of a heating circuit for a discharge lamp. For this purpose, the frequency of a supply voltage for the resonant circuit is varied within a predetermined frequency range. The voltage or the current across/in the resonant circuit are measured as a function of the varied frequency. The predetermined frequency range is run through in both directions, in each case a maximum for the measured voltage or the measured current being established. The resonant frequency is preferably calculated from the two maxima by averaging.

Abstract: The invention relates to a ballast for a lamp having an inverter which includes at least one switch (S1; S2), and having a drive circuit (10) for alternately opening and closing the at least one switch (S1; S2) wherein the drive circuit (10) is designed to drive the at least one switch (S1; S2) alternately at at least two different frequencies (&ohgr;a, &ohgr;b). It also relates to a method for operating a ballast for a lamp having an inverter which comprises at least one switch (S1; S2), and having a drive circuit (10) for alternately opening and closing the at least one switch (S1; S2) wherein the drive circuit drives the at least one switch (S1; S2) alternately at at least two different frequencies (&ohgr;a, &ohgr;b).

Abstract: A novel operating circuit for a low-pressure gas discharge lamp 1 in the case of which a digital controller 12 is designed such that by gradually lowering the operating frequency in the ignition procedure it initiates shutdown operations of a safety shutdown device for excessive currents through a lamp inductor 10 in order thereafter to increase the operating frequency somewhat. It is possible overall in this way to achieve an ignition, for example by repeated pulsed ignition operations as far as shutdown operations, or else by a continuous ignition operation at a minimum frequency at which no shutdown operation occurs. The invention has the advantage of being insensitive to temperature fluctuations and component tolerances and, moreover, of permitting the lamp inductor 10 to have comparatively small dimensions.

Abstract: An operating circuit for a discharge lamp (LP) having preheatable electrodes includes a device (C14, T11, T12, T13, G) for preheating the electrodes. The device includes a resonant circuit (C14, T11) which oscillates during preheating. During operation, the operating circuit produces an AC voltage having a frequency that is moved through a frequency range, records the response of the resonant circuit (C14, T11) by measuring an electrical variable (UC14), and identifies the resonant frequency of the resonant circuit (C14, T11) from the electrical variable (UC14), and preheats the electrodes by setting the frequency of the AC voltage to the resonant frequency.