A lighting device for a motor vehicle including a processing module which is configured to receive and process signals of a data bus of the motor vehicle and send a data signal. The lighting device also includes an LED unit configured to emit light, when operational, with an adjustable brightness and a predefined color location. The LED unit has a microcontroller and a plurality of LEDs, and the microcontroller and the plurality of LEDs are surrounded by a housing of the LED unit. Furthermore, the processing module is configured to convert the data signal, which contains control information for the LED unit, into a pulse width-modulated signal of the current supplied to the individual LEDs and to verify whether the pulse width-modulated signal contains information corresponding to the control information for the LED unit.

An airfield runway lamp controller is described herein. One airfield runway lamp controller includes a current sense transformer configured to detect a failure of a light source of an airfield runway lamp, and an alternating current (AC) switch configured to shunt the light source of the airfield runway lamp upon the current sense transformer detecting a failure of the light source.

A lighting system (1) comprises a power unit (20) for producing data-modulated current, and a light unit (10) receiving this current at its input and output terminals (11, 12). The light unit comprises two or more light modules (100A; 100B; 100C) connected in series. Each light module comprises: a LED string (110) of one or more LEDs (111, 112, 113) connected between module input and output terminals (101, 102), each LED having an associated controllable shunt switch (121, 122, 123) connected in parallel thereto; a module controller (190) for controlling the shunt switches, the module controller (190) having a input terminals (191, 192) connected to said module input and output terminals, respectively. The module controller demodulates the data and controls the switches on the basis of an action command contained therein, if an address information contained therein matches the unique controller address.

A resistor bypass circuit for a series lighting circuit includes a plurality of serially connected light sources and a bypass resistor being connected in parallel with at least one of the respective light sources, each respective light source being low wattage and being capable operating on a one hundred percent duty cycle as desired.

A resistor bypass circuit for a series lighting circuit includes a plurality of serially connected light sources and a bypass resistor being connected in parallel with at least one of the respective light sources, each respective light source being low wattage and being capable operating on a one hundred percent duty cycle as desired.

A LED lighting circuit has a plurality of LED segments connected in series. A switching arrangement is used to selectively bypass at least one LED segment to implement a tapped linear driver approach. Degrading of a component in the LED lighting circuit is detected, so that a first TLD current modulation scheme is implemented when no such degrading is detected whereas a second current modulation scheme, different from the first current modulation scheme, is implemented to compensate for said degrading. Said degrading is leading to an increase in a turning on voltage of one LED segment, and compared to said first current modulation scheme, said second current modulation scheme has a higher voltage threshold at which said LED segment is switched. In this way, protection may be provided for circuit components and the light output may be maintained at the desired level in the event of component degrading, such as LED chip failure or contact resistance changes.

Provided is a light source apparatus including semiconductor light sources and a current detection resistor connected in series, a power source circuit that allows current to flow thereto, a current detection circuit that detects current flowing to the current detection resistor and outputs a current detection signal, a control circuit that controls the power source circuit such that a voltage of the current detection signal approaches a target value, a bypass circuit connected in parallel to the semiconductor light sources, and including a clamp element having a clamp voltage higher than a maximum voltage during operation of the semiconductor light sources and a bypass resistor connected in series to the clamp element, and allowing current to flow when an open fault occurs in the semiconductor light sources, and detection circuits that respectively detect an open fault in the semiconductor light sources based on an end-to-end voltage of the bypass resistors.

Provided is a light source apparatus including semiconductor light sources and a current detection resistor connected in series, a power source circuit that allows current to flow thereto, a current detection circuit that detects current flowing to the current detection resistor and outputs a current detection signal, a control circuit that controls the power source circuit such that a voltage of the current detection signal approaches a target value, a bypass circuit connected in parallel to the semiconductor light sources, and including a clamp element having a clamp voltage higher than a maximum voltage during operation of the semiconductor light sources and a bypass resistor connected in series to the clamp element, and allowing current to flow when an open fault occurs in the semiconductor light sources, and detection circuits that respectively detect an open fault in the semiconductor light sources based on an end-to-end voltage of the bypass resistors.

A LED lighting circuit has a plurality of LED segments connected in series. A switching arrangement is used to selectively bypass at least one LED segment to implement a tapped linear driver approach. Degrading of a component in the LED lighting circuit is detected, so that a first TLD current modulation scheme is implemented when no such degrading is detected whereas a second current modulation scheme, different from the first current modulation scheme, is implemented to compensate for said degrading. Said degrading is leading to an increase in a turning on voltage of one LED segment, and compared to said first current modulation scheme, said second current modulation scheme has a higher voltage threshold at which said LED segment is switched. In this way, protection may be provided for circuit components and the light output may be maintained at the desired level in the event of component degrading, such as LED chip failure or contact resistance changes.

An installation powers and controls a plurality of signaling lights arranged in series, each having at least one light source. The installation includes a unit with a primary power supply situated upstream for remotely programming or managing operation of the installation; a primary series circuit with a transformer for each signaling light; a control module for each signaling light; a secondary power supply circuit for powering the control modules, independent of the primary circuit; a first optical cable for bi-directionally connecting a first upstream module to the programming or managing unit; and a second optical cable for bi-directionally connecting a last downstream control module to the programming/management unit, with each control module being connected in series to an adjacent upstream module and to an adjacent downstream module by means of a respective bi-directional optical connection.