Abstract: A controller for a lamp, comprising an input terminal for receiving a requested-color-signal representative of a requested-color-value to be provided by the lamp and one or more temperature-values associated with the lamp. The controller includes a full-color-module for providing a full-color-lamp-control-signal for an output terminal; a stabilization-module for providing a stabilized-lamp-control-signal for the output terminal; and a mode controller for comparing the requested-color-value with a threshold value. If the requested-color-value satisfies the threshold value, then the stabilization-module provides the stabilized-lamp-control-signal to the output terminal. If the requested-color-value does not satisfy the threshold value, then the full-color-module provides the full-color-lamp-control-signal to the output terminal.

Abstract: A controller for a lamp, comprising an input terminal for receiving a requested-colour-signal representative of a requested-colour-value to be provided by the lamp and one or more temperature-values associated with the lamp. The controller includes a full-colour-module for providing a full-colour-lamp-control-signal for an output terminal; a stabilization-module for providing a stabilized-lamp-control-signal for the output terminal; and a mode controller for comparing the requested-colour-value with a threshold value. If the requested-colour-value satisfies the threshold value, then the stabilization-module provides the stabilized-lamp-control-signal to the output terminal. If the requested-colour-value does not satisfy the threshold value, then the full-colour-module provides the full-colour-lamp-control-signal to the output terminal.

Abstract: A method, controller and lighting circuit are disclosed: the variation of chromaticity and luminosity of LEDs as a function of temperature over an operating temperature range is characterized; virtual LEDs, including a virtual white are defined, such that the chromaticity of each virtual LED can be achieved by combining component light from the LEDs for all temperatures within the operating range; the requested settings R, G, B of each of three primary colors, defining a requested chromaticity and a requested luminance, are used to determine a virtual white control setting corresponding to a maximum fraction of a total luminance at the requested chromaticity which can be provided by the virtual white LED; control settings for each of the other LEDs are thereby determined, and the setting for each of the LEDs is determined from the sum of that LED's component of the virtual LEDs.

Abstract: An LED lighting system is disclosed comprising: a heatsink; a plurality of strings of LEDs each string comprising one or more LEDs each having a junction and being mounted on the heatsink, and a controller comprising a memory unit and a processor and being configured to supply a current to each of the strings of LEDs; the processor comprises: a first temperature estimation subunit configured to generate an estimate of a temperature of the junction of a one of strings of LEDs; a heatsink temperature estimation subunit configured to estimate a temperature of the heatsink unit from the first estimate; and a second temperature estimation subunit configured to provide an estimate of a temperature of the junction of a second string of LEDs, from the estimated temperature of the heatsink. A controller for and method of operating a plurality of LEDs are also disclosed.

Abstract: A method, controller and lighting circuit are disclosed: the variation of chromaticity and luminosity of LEDs as a function of temperature over an operating temperature range is characterised; virtual LEDs, including a virtual white are defined, such that the chromaticity of each virtual LED can be achieved by combining component light from the LEDs for all temperatures within the operating range; the requested settings R, G, B of each of three primary colours, defining a requested chromaticity and a requested luminance, are used to determine a virtual white control setting corresponding to a maximum fraction of a total luminance at the requested chromaticity which can be provided by the virtual white LED; control settings for each of the other LEDs are thereby determined, and the setting for each of the LEDs is determined from the sum of that LED's component of the virtual LEDs.

Abstract: An LED lighting system is disclosed comprising: a heatsink; a plurality of strings of LEDs each string comprising one or more LEDs each having a junction and being mounted on the heatsink, and a controller comprising a memory unit and a processor and being configured to supply a current to each of the strings of LEDs; the processor comprises: a first temperature estimation subunit configured to generate an estimate of a temperature of the junction of a one of strings of LEDs; a heatsink temperature estimation subunit configured to estimate a temperature of the heatsink unit from the first estimate; and a second temperature estimation subunit configured to provide an estimate of a temperature of the junction of a second string of LEDs, from the estimated temperature of the heatsink. A controller for and method of operating a plurality of LEDs are also disclosed.