Abstract: The present invention is based on a regulation circuit (200a, 200b) for making available a constant current supply on the basis of a transformer principle, in which there flows through the luminescent diodes (D1, . . . , DN) a triangular a.c. current (ID) varying periodically around a d.c. current value. With this method it is afforded by means of a circuitry provision that both the charging and also the discharging current (IL1) of an inductive reactance (XL1) connected in series to the luminescent diodes (D1, . . . , DN), functioning as a storage choke (L1) for filtering of mains harmonics, flows as diode current (ID) through the luminescent diodes (D1, . . . , DN). The advantage of this method consists in a significant reduction of the overall power loss (PV, ges) of the LED illumination module (100).

Abstract: The present invention is based on a regulation circuit for making available a constant current supply on the basis of a transformer principle, in which there flows through the luminescent diodes (D1, . . . , DN) a triangular a.c. current varying periodically around a DC current value. Both a charging and a discharging current of inductive reactance connected in series to the luminescent diodes (D 1, . . . , DN), functioning as a storage choke for filtering of mains harmonics, flows as diode current through the luminescent diodes (D 1, . . . , DN). According to one exemplary embodiment of the invention the ceramic circuit board of the LED illumination module in accordance with the invention has a direct mains current supply, which for protection from mechanical damage is accommodated in a transparent housing having a highly transparent polymer mass serving as optically active lens surface.

Abstract: The present invention is based on a regulation circuit (200a, 200b) for making available a constant current supply on the basis of a transformer principle, in which there flows through the luminescent diodes (D1, . . . ,DN) a triangular a.c. current (ID) varying periodically around a d.c. current value. With this method it is afforded by means of a circuitry provision that both the charging and also the discharging current (IL1) of an inductive reactance (XL1) connected in series to the luminescent diodes (D1, . . . ,DN), functioning as a storage choke (L1) for filtering of mains harmonics, flows as diode current (ID) through the luminescent diodes (D1, . . . ,DN). The advantage of this method consists in a significant reduction of the overall power loss (PV,ges) of the LED illumination module (100).

Abstract: The present invention is based on a regulation circuit (200a, 200b) for making available a constant current supply on the basis of a transformer principle, in which there flows through the luminescent diodes (D1, . . . ,DN) a triangular a.c. current (ID) varying periodically around a d.c. current value. With this method it is afforded by means of a circuitry provision that both the charging and also the discharging current (IL1) of an inductive reactance (XL1) connected in series to the luminescent diodes (D1, . . . ,DN), functioning as a storage choke (L1) for filtering of mains harmonics, flows as diode current (ID) through the luminescent diodes (D1, . . . ,DN). The advantage of this method consists in a significant reduction of the overall power loss (PV, ges) of the LED illumination module (100).

Abstract: A circuit arrangement comprises four controllable switches (S1, S4) interconnected to form a full bridge. A warm-up operation is carried out in which there is a switch over between the two bridge diagonals (S1, S4; S2, S3) respectively. The gas discharge lamp (EL) is ignited by way of a series resonant circuit (L1, C1) which is coupled to the bridge branch. The actual normal operation is effected by switching over at a low frequency between the switches of the two bridge diagonals (S1, S4; S2, S3), with, moreover, one switch (S1, S2) of the respectively activated bridge diagonal being switched on and off alternately at a high frequency, with this switch (S1, S2) being switched on at the high frequency whenever the current (iL2) flowing by way of the bridge branch has reached a minimum value.

Abstract: Method for operating a ballast for discharge lamps. The ballast comprises a rectifier for rectifying and filtering an AC line voltage, with the rectified voltage being smoothed with a capacitor and fed to an inverter, wherein the inverter drives a resonant lamp circuit that includes a gas discharge lamp, with the frequency of the inverter being generated by a voltage controlled oscillator and a control circuit, so that during normal operation of the lamp, the inverter frequency is chosen according to the current value of the rectified voltage, and during start-up of the ballast, the inverter frequency is lowered from a high starting frequency, while being continuously monitored to ensure the latter does not fall below a minimum frequency, with the value of the minimum frequency depending on the value of the rectified voltage, thus decreasing the dependence of the light flux on the rectified voltage and assuring a safe start-up process.

Abstract: Driver circuit for discharge lamps. The driver circuit contains an inverter driving a lamp circuit with a discharge lamp and the current in the lamp circuit is measured as a voltage U.sub.ILC over a resistor, with a control circuit comprising a strike detector that determines if the lamp did strike during a start-up phase of the driver, and if not, the inverter is switched off, with the control circuit going into a monitoring state where it operates the inverter for short periods at regular intervals, and during each such period, the voltage U.sub.ILC is monitored to detect a removal or an insertion of a lamp, so that, once the lamp has been replaced, a new start-up phase begins.

Abstract: In an electrical circuit for feeding a fluorescent lamp, a serial resonant circuit is comprised of a first coil of a feedback-transformer, a resonant inductor, a coupling condenser, a first lamp cathode, a resonant condenser, and a first coil of an isolating transformer, this serial resonant circuit being connected between the output of an inverted rectifier, connected to a voltage supply source and one terminal of said voltage supply source, with a second coil of the isolating transformer being connected in parallel with the second lamp cathode. If the coils of the isolating transformer have the same number of loops, this connection of the second lamp cathode ensures that the same heating current will flow through both lamp cathodes, so that these will be heated equally. The parallel circuit of the second lamp cathode with the second coil of the isolating transformer is connected through a resistance with a terminal of the supply voltage.

Abstract: Method and apparatus for igniting fluorescent lamps at a predetermined temperature of their cathodes. In the present invention, it is the resistance of the cold lamp cathodes that is always measured and ignition occurs as a result of the relationships or conditions of the cold resistance to the hot resistance or the voltage relationship of cold to hot, so that the absolute value has no influence and correct preheating is achieved with all types of lamps.

Abstract: A device for protecting a ballast circuit from excess voltage and excess current includes a switch for disconnecting the ballast circuit from the power source and a control circuit for operating this switch; the control circuit monitoring a control point, from which control point a first resistor connects to a first terminal of the power source, a second resistor connects to a second terminal of the power source, and a third resistor connects to a point between the switch and the ballast, the switch being brought into off-state when the voltage between the control point and the first terminal of the power source exceeds a given value, thus leading to a hysteresis between an input voltage for switching the device off and an input voltage for switching the device back on again, with positive feedback being provided by the third resistor for decreasing the switch-off time and the corresponding switching losses.