Abstract: The present invention relates to an LED lamp (1) adapted for operation with an alternating current. The LED retrofit lamp (1) comprises a LED unit (7, 7?, 7?, 7??) and a compensation circuit with a controllable switching device (9, 9?), connected parallel to said LED unit (7, 7?, 7?, 7??) to provide an alternate current path. A control unit (10, 10?, 10?) is adapted to control said switching device (9, 9?) in a compensation mode in which said switching device (9, 9?) is set to the conducting state for the duration of a shunt period in each half cycle of the alternating current to allow adapting the power/current of the inventive LED lamp (1), so that a versatile and optimized operation of the lamp (1) is possible.

Abstract: Driver circuits (1) for driving loads (2) comprising light emitting diodes are provided with rectifiers (11-14) for exchanging first current signals with fluorescent ballasts (3) such as active electronic ballasts and for supplying second current signals to the loads (2), with switch circuits (21-27) coupled to or forming part of the rectifiers (11-14) for controlling amounts of power supplied to the loads (2), and with controllers (31) for controlling the switch circuits (21-27) such that switching frequencies of the switch circuits (21-27) are equal to or lower than twice the frequencies of the first current signals. Detuning circuits (4) match output impedances of the fluorescent ballasts (3) and input impedances of the rectifiers (11-14). Start-up circuits (5) increase impedances at input terminals of the rectifiers (11-14) at start-up. Current sensors (6) and voltage sensors (7) provide feedback.

Abstract: An electric lamp (1) has two pairs of external connection pins (5) adapted for connecting the lamp to a voltage source for powering an internal lighting module (3). Each pair of pins is disconnected from the lighting module by an open switch (6) unless a non-zero electric voltage is applied to the pair and causes the switch to close. The lamp is therefore safe to handle even in a condition where one pair of pins is connected and the other is not. The lamp may be fitted in a switch-start fixture, providing an ohmic connection between two pins in different pairs, as well as a rapid-start fixture, with a capacitive connection.

Abstract: An electric lamp (1) has two pairs of external connection pins (5) adapted for connecting the lamp to a voltage source for powering an internal lighting module (3). Each pair of pins is disconnected from the lighting module by an open switch (6) unless a non-zero electric voltage is applied to the pair and causes the switch to close. The lamp is therefore safe to handle even in a condition where one pair of pins is connected and the other is not. The lamp may be fitted in a switch-start fixture, providing an ohmic connection between two pins in different pairs, as well as a rapid-start fixture, with a capacitive connection.

Abstract: In a lighting device, sets of LEDs are employed using the natural characteristics of the LEDs to resemble incandescent lamp behavior when dimmed, thereby Obviating the need for sophisticated controls. A first set of at least one LED produces light with a first color temperature, and a second set of at least one LED produces light with a second color temperature. The first set and the second set are connected in series, or the first set and the second set are connected in parallel, possibly with a resistive element in series with the first or the second set. The first set and the second set differ in temperature behavior, or have different dynamic electrical resistance. In various embodiments, the sum of the currents provided to the first and second sets may be substantially equal to a magnitude of an input current.

Abstract: A lighting driver includes a shunt switch circuit configured to detect when an input of the lighting driver is connected to mains power without a ballast, and in response thereto to disable the lighting driver, and further configured to detect a type of ballast connected to the input of the lighting driver when the input of the lighting driver is connected to the ballast, and to regulate a bus voltage of the shunt switch circuit according to the detected type of ballast; and a switching mode power supply configured to receive the bus voltage of the shunt switch circuit and in response thereto to supply a lamp current to drive one or more light emitting diodes.

Abstract: In a lighting device, sets of LEDs are employed using the natural characteristics of the LEDs to resemble incandescent lamp behavior when dimmed, thereby obviating the need for sophisticated controls. A first set of at least one LED produces light with a first color temperature, and a second set of at least one LED produces light with a second color temperature. The first set and the second set are connected in series, or the first set and the second set are connected in parallel, possibly with a resistive element in series with the first or the second set. The first set and the second set differ in temperature behavior, or have different dynamic electrical resistance. The light device produces light with a color point parallel and close to a blackbody curve.

Abstract: The present invention relates to an LED lamp (1) adapted for operation with an alternating current. The LED retrofit lamp (1) comprises a LED unit (7, 7?, 7?, 7??) and a compensation circuit with a controllable switching device (9, 9?), connected parallel to said LED unit (7, 7?, 7?, 7??) to provide an alternate current path. A control unit (10, 10?, 10?) is adapted to control said switching device (9, 9?) in a compensation mode in which said switching device (9, 9?) is set to the conducting state for the duration of a shunt period in each half cycle of the alternating current to allow adapting the power/current of the inventive LED lamp (1), so that a versatile and optimized operation of the lamp (1) is possible.

Abstract: A lighting device has a plurality of LEDs connected in series. In the lighting device, a first LED assembly has LEDs of a first type having a first luminous flux output decreasing as a first function of its junction temperature. A second LED assembly has LEDs of a second type having a second luminous flux output decreasing as a second function of its junction temperature different from the first function. At least one of the LEDs of the first type and LEDs of the second type is connected in parallel to a resistor assembly having a temperature-dependent resistance. The temperature dependence of the resistance stabilizes a ratio of the first luminous flux output to the second luminous flux output at different junction temperatures of the first LED assembly and the second LED assembly.

Abstract: In a lighting device, sets of LEDs are employed using the natural characteristics of the LEDs to resemble incandescent lamp behavior when dimmed, thereby obviating the need for sophisticated controls. A first set of at least one LED produces light with a first color temperature, and a second set of at least one LED produces light with a second color temperature. The first set and the second set are connected in series, or the first set and the second set are connected in parallel, possibly with a resistive element in series with the first or the second set. The first set and the second set differ in temperature behavior, or have different dynamic electrical resistance. The light device produces light with a color point parallel and close to a blackbody curve.

Abstract: The display device (6) comprises a display (2) and generating means (10,8). The display (2) has a plurality of light emitting elements (3), and data lines (13) for providing pulse width modulation (PWM) signals to the light emitting elements (3). The generating means (10, 8) are coupled to the data lines (13) for generating, during time intervals (SF) of a frame period, at least a first non-zero emission level (L(V1; C1; I1)) of a light emitting element (3) during a first one of the time intervals (SF) and a second non-zero emission level (L(V2; C2; 12)) during a second one of the time intervals (SF).

Abstract: The display device (1) comprises picture elements (5) arranged in substantially parallel lines (6) on a display panel (2), and selection means (3) for controlling the decoupling of light from an optical waveguide plate at the picture elements. The selection means (3) are arranged for multiline addressing of the picture elements (5). For displaying gray scales, image information (4) is decomposed into a number of subfields (13) which are displayed. The time efficiency of the addressing of picture elements (5) in lines (16) in the subfields (13) is increased, enabling the display device (1) to display a relative large number of gray method of operating a display device (1) is carried out when the device is in operation.