Abstract: The invention relates to an electronic ballast for a discharge lamp LA1 having an EOL monitoring circuit R1, R2, U1, R9, U2-A, U2-B, U3-A, AE, which has a current differential amplifier U1 having a current mirror input.

Abstract: The invention relates to a novel ballast for a discharge lamp, in which a continuous-operation control circuit is brought out of operation when a physical operation, which defines a preheating time, of a preheating timer has as yet not been sufficiently returned if the lamp is intended to be restarted.

Abstract: The usual xenon radiation source in conventional weathering testers is replaced by UV light-emitting diodes (LEDs) (6). These can be used to provide a good approximation of the UV component of the solar spectrum, in particular when different types of UV light-emitting diodes (6) with different emission characteristics are employed. Optionally, further light-emitting diodes in the visible spectral range may also be used in order to cover other parts of the solar spectrum. The light-emitting diodes (6) may be mounted on a flexible printed circuit board (5), which may in turn be fitted on a tubular holding body (4). The flexible printed circuit board carrying the light-emitting diodes may also be placed on other substrates (7) which are pliable in a geometrically stable way, so that that they can be arranged at a uniform distance from material samples with a particular surface topology, in order to obtain uniform exposure.

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: Circuit arrangement having a free-running half-bridge inverter for operation of gas discharge lamps. A stop device is used to enable the drive to the half-bridge switches only during an on time. The oscillation frequency of the half-bridge inverter can be adjusted by the duration of the on time. This allows control of the lamp operating variables.

Abstract: The invention relates to an electronic ballast for discharge lamps LA1, LA2 having preheatable electrodes which has a pump circuit D5/D7, D6/D8 for improving the power factor. In this arrangement, preheating is performed with a converter frequency, raised by comparison with continuous operation, and with the aid of a preheating transformer TR2.

Abstract: The invention relates to an electronic ballast for operating a discharge lamp LA, in which a pump circuit D6, C8, C9, L1 charges an intermediate circuit capacitor C6 from the AC voltage of a converter V1, V2. A voltage limitation circuit R8, R3, D5, R4, R5, C3, SD is connected in parallel with the intermediate circuit capacitor C6. A dissipation element R8 in the voltage limitation circuit R8, R3, D5, R4, R5, C3, SD converts electrical energy into thermal energy when a maximum value for the voltage across the intermediate circuit capacitor C6 is exceeded. The current through the measuring resistor R3 is measured as the voltage UC3 across the measuring resistor R3, is detected in a delay circuit R4, R5, C3 and is used to control a shutdown device SD for the converter V1, V2.

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 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 invention relates to an electronic ballast for operating a discharge lamp LA, in which a pump circuit D6, C8, C9, L1 charges an intermediate circuit capacitor C6 from the AC voltage of a converter V1, V2. A voltage limitation circuit R8, R3, D5, R4, R5, C3, SD is connected in parallel with the intermediate circuit capacitor C6. A dissipation element R8 in the voltage limitation circuit R8, R3, D5, R4, R5, C3, SD converts electrical energy into thermal energy when a maximum value for the voltage across the intermediate circuit capacitor C6 is exceeded. The current through the measuring resistor R3 is measured as the voltage UC3 across the measuring resistor R3, is detected in a delay circuit R4, R5, C3 and is used to control a shutdown device SD for the converter V1, V2.

Abstract: Circuit arrangement having a free-running half-bridge inverter for operation of gas discharge lamps. A stop device is used to enable the drive to the half-bridge switches only during an on time. The oscillation frequency of the half-bridge inverter can be adjusted by the duration of the on time. This allows control of the lamp operating variables.

Abstract: Drive circuit for operating at least one lamp in an associated load circuit, in which terminals for the lamp are arranged, having two switches in a half-bridge arrangement, each switch including a cascode circuit of a bipolar transistor having a control, a working and a reference electrode, and a field-effect transistor having a control, a working and a reference electrode. The center point of the half-bridge arrangement is coupled to the load circuit, and each cascode circuit has an input circuit, in which a diode and a secondary winding of a transformer, connected in series, are arranged in parallel with the control electrode of the bipolar transistor and the reference electrode of the field-effect transistor, the primary winding of the transformer being arranged in the load circuit such that the load circuit current flows through it when operating the lamp.

Abstract: The invention relates to an electronic ballast for discharge lamps LA1, LA2 having preheatable electrodes which has a pump circuit D5/D7, D6/D8 for improving the power factor. In this arrangement, preheating is performed with a converter frequency, raised by comparison with continuous operation, and with the aid of a preheating transformer TR2.

Abstract: The radiation power emitted from the UV radiation sources (2) in a weathering apparatus is controlled such that the radiation power of each of the radiation sources (2) is measured in a predetermined spectral range of the radiation emitted from the radiation sources, with the spectral range being chosen such that the measured radiation power is representative of the radiation power in the UV, an averaged radiation power is calculated from the measured radiation powers, and the averaged radiation power is used for controlling the electrical power to be supplied to the radiation sources (2). In particular, the control process can be carried out in such a way that the same electrical power, within a predetermined tolerance bandwidth, is supplied to each of the radiation sources (2), and the averaged radiation power is kept constant over time at a desired nominal value.

Abstract: The invention relates to a novel ballast for a discharge lamp, in which a continuous-operation control circuit is brought out of operation when a physical operation, which defines a preheating time, of a preheating timer has as yet not been sufficiently returned if the lamp is intended to be restarted.

Abstract: Circuit arrangement for starting and operating discharge lamps (Lp1, Lp2) with control of the lamp current and preheating of electrode filaments. No control device is required for the sequence of the preheating, igniting and operating phases. This is achieved by a preheating resistor which changes its value after the preheating phase, in combination with controller properties according to the invention.

Abstract: In the case of circuit arrangements for operating discharge lamps (Lp1, Lp2) which include a charge pump for reducing line current harmonics, an energy imbalance occurs when the lamps are started. In order for this not to lead to components being destroyed, but for sufficient ignition voltage nevertheless to be generated at the lamps (Lp1, Lp2), a threshold switch (MOV, TH) monitors the frequency of an inverter included in the circuit arrangement.