Abstract: A monitor device is provided for monitoring a lighting arrangement of lighting elements of unknown electrical load, and a driver using the monitoring arrangement. A set of duty cycles is applied to switches which control sub-sets of lighting elements thereby to create a desired light output. With this desired duty cycle setting, the current for an individual duty cycle period is monitored, in particular to detect variations in a current plateau level within the individual duty cycle period. This is used to determine electrical characteristics or parameters including at least a cable resistance between a power supply unit and the lighting arrangement. A power consumption of the lighting arrangement may then be obtained. This avoids the need to probe the sub-sets of lighting elements individually in order to determine the nature of the load and its power consumption.

Abstract: A method of activating at least one light source comprises reading (109) a value from a memory of a light device upon the light device being powered on. The value depends on how long the light device was continuously powered on before the light device was last powered off. The method further comprises determining (203) from the value whether the light device was continuously powered on for more than a predetermined period before the light device was last powered off and activating (213) the at least one light source in dependence on the determination.

Abstract: A method of activating at least one light source comprises reading (109) a value from a memory of a light device upon the light device being powered on. The value depends on how long the light device was continuously powered on before the light device was last powered off. The method further comprises determining (203) from the value whether the light device was continuously powered on for more than a predetermined period before the light device was last powered off and activating (213) the at least one light source in dependence on the determination.

Abstract: A monitor device is provided for monitoring a lighting arrangement of lighting elements of unknown electrical load, and a driver using the monitoring arrangement. A set of duty cycles is applied to switches which control sub-sets of lighting elements thereby to create a desired light output. With this desired duty cycle setting, the current for an individual duty cycle period is monitored, in particular to detect variations in a current plateau level within the individual duty cycle period. This is used to determine electrical characteristics or parameters including at least a cable resistance between a power supply unit and the lighting arrangement. A power consumption of the lighting arrangement may then be obtained. This avoids the need to probe the sub-sets of lighting elements individually in order to determine the nature of the load and its power consumption.

Abstract: A lighting control circuit is for controlling a lighting arrangement comprising a set of at least two light sources in parallel. A current driver is used to deliver a drive current to the lighting arrangement. A switch is associated with the second light source, which may for example be provided for color adjustment, and the duty cycle of the switch is controlled as well as the overall drive current setting thereby to control the color or color temperature setting and dimming level of the lighting arrangement. The controller derives the required average output current and the expected average output voltage from the current driver based on the determined duty cycle and the dimming level, and then derives the current driver setting. In this way, the current driver is accurately controlled to deliver the required output. This enables a single stage driver to be used to control the color or color temperature of multiple light source channels, for example in dependence on a dimming level.

Abstract: A lighting control circuit is for controlling a lighting arrangement comprising a set of at least two light sources in parallel. A current driver is used to deliver a drive current to the lighting arrangement. A switch is associated with the second light source, which may for example be provided for color adjustment, and the duty cycle of the switch is controlled as well as the overall drive current setting thereby to control the color or color temperature setting and dimming level of the lighting arrangement. The controller derives the required average output current and the expected average output voltage from the current driver based on the determined duty cycle and the dimming level, and then derives the current driver setting. In this way, the current driver is accurately controlled to deliver the required output. This enables a single stage driver to be used to control the color or color temperature of multiple light source channels, for example in dependence on a dimming level.

Abstract: Determination devices (1) determine properties of load devices (2) that may remain unchanged for said determining and that comprise first channels with first elements (20, 25). The determination devices comprise first switches (10) for providing first invitation signals to the first channels, detectors (15, 16) for detecting first response signals that result from the first invitation signals, and controllers (17) for deriving the properties of the load devices (2) from detections of the first response signals. The properties define first maximum values of first loads of the first channels, and the controllers (17) calculate first maximum duty cycles of first supply signals for supplying the first channels in view of the first maximum values of the first loads and power capacities of power supplies (3) that produce the first supply signals. The load devices (2) may further comprise second channels with second elements (21, 26), and the determination devices (1) may further comprise second switches (11).

Abstract: Determination devices (1) determine properties of load devices (2) that may remain unchanged for said determining and that comprise first channels with first elements (20, 25). The determination devices comprise first switches (10) for providing first invitation signals to the first channels, detectors (15, 16) for detecting first response signals that result from the first invitation signals, and controllers (17) for deriving the properties of the load devices (2) from detections of the first response signals. The properties define first maximum values of first loads of the first channels, and the controllers (17) calculate first maximum duty cycles of first supply signals for supplying the first channels in view of the first maximum values of the first loads and power capacities of power supplies (3) that produce the first supply signals. The load devices (2) may further comprise second channels with second elements (21, 26), and the determination devices (1) may further comprise second switches (11).