Abstract: Light source circuitry comprises a first group of one or more light emitting diodes operable to emit light of a first color, a second group of one or more light emitting diodes operable to emit light of a second color, and a third group of one or more light emitting diodes operable to emit light of a third color, wherein the first, second and third groups of light emitting diodes are arranged such that, when a fixed current arrives at the light source circuitry, the fixed current is shared between the first, second and third groups, and wherein the circuitry is configured such that a proportion of the fixed current that flows through each of the first and second groups is controllable in dependence on a received control signal and such that the remainder of the fixed current flows through the third group.

Abstract: Light source circuitry comprises a first group of one or more light emitting diodes operable to emit light of a first color, a second group of one or more light emitting diodes operable to emit light of a second color, and a third group of one or more light emitting diodes operable to emit light of a third color, wherein the first, second and third groups of light emitting diodes are arranged such that, when a fixed current arrives at the light source circuitry, the fixed current is shared between the first, second and third groups, and wherein the circuitry is configured such that a proportion of the fixed current that flows through each of the first and second groups is controllable in dependence on a received control signal and such that the remainder of the fixed current flows through the third group.

Abstract: An LED lighting device may include a first constant current source, a switched mode power supply, a plurality of LEDs between the switched mode power supply and the first constant current source, and powered by the switched mode power supply, and a voltage divider between the switched mode power supply and the plurality of LEDs. In various embodiments, the voltage divider may include a plurality of switches. Each switch may be configured to transition between open and closed based on a lighting state of an LED of the plurality of LEDs to vary a divided feedback voltage provided to the switched mode power supply. In various embodiments, the switched mode power supply may be configured to supply different output voltages based on the divided feedback voltage.

Abstract: The present invention relates to a multiple LED driver circuit in which each LED (15, 17) is controlled by a bypass switch (19, 21). The LEDs are supplied by a switched mode power supply (8) and are connected to a constant current source to draw a predetermined current through the LEDs. The switched mode power supply is arranged to output different voltages depending on the number of switched-on LEDs. This is carried out by supplying the control signals (sw1, sw2) of the bypass switches to the switched mode power supply. In this way, the power dissipation of the constant current source can be kept at a low level.

Abstract: An LED lighting device may include a first constant current source, a switched mode power supply, a plurality of LEDs between the switched mode power supply and the first constant current source, and powered by the switched mode power supply, and a voltage divider between the switched mode power supply and the plurality of LEDs. In various embodiments, the voltage divider may include a plurality of switches. Each switch may be configured to transition between open and closed based on a lighting state of an LED of the plurality of LEDs to vary a divided feedback voltage provided to the switched mode power supply. In various embodiments, the switched mode power supply may be configured to supply different output voltages based on the divided feedback voltage.

Abstract: A switched mode power supply assembly (1) is described, comprising at least two switched mode power supply units (10i) coupled to each other in parallel; each power supply unit (10i) having an output stage (50i, 60i) capable of selectively operating in a first mode wherein its output signal (IOUT,I) is increasing and operating in a second mode wherein its output signal (IOUT,i) is decreasing; a control device (100) receiving mode switch control signals from all power supply units (10i); wherein the control device (100), if it finds that the actual phase relationship between two power supply units deviates from an optimal phase relationship, is designed to generate synchronising control signals for at least one power supply unit (102), effectively changing the timing of at least one mode switch moment, such that the deviation between the actual phase relationship and said optimal phase relationship is reduced.

Abstract: A drive circuit (1) for driving a load (3) comprises: a switched mode power supply (10) for supplying at the output (2a, 2b) a switched output current (IL); a controller (20) for controlling the power supply; a current sensor (15) for generating a current sense signal (Vi 5) representing the output current (IL); a voltage sensor (30) for generating a voltage sense signal (Sy) representing the output voltage (Vp; Vp+Vis) of the circuit. The controller receives the current sense signal, and generates a switching time control signal (Sc) for the switched mode power supply (10) on the basis of the current sense signal. The controller further receives the voltage sense signal. In response to a change in the voltage sense signal, the controller changes the switching time control signal such as to effectively compensate an effect of the output voltage change on the average value of the output current.

Abstract: The present invention relates to a multiple LED driver circuit in which each LED (15, 17) is controlled by a bypass switch (19, 21). The LEDs are supplied by a switched mode power supply (8) and are connected to a constant current source to draw a predetermined current through the LEDs. The switched mode power supply is arranged to output different voltages depending on the number of switched-on LEDs. This is carried out by supplying the control signals (sw1, sw2) of the bypass switches to the switched mode power supply. In this way, the power dissipation of the constant current source can be kept at a low level.

Abstract: The present invention relates to a multiple LED driver circuit in which each LED (15, 17) is controlled by a bypass switch (19, 21). The LEDs are supplied by a switched mode power supply (8) and are connected to a constant current source to draw a predetermined current through the LEDs. The switched mode power supply is arranged to output different voltages depending on the number of switched-on LEDs. This is carried out by supplying the control signals (sw1, sw2) of the bypass switches to the switched mode power supply. In this way, the power dissipation of the constant current source can be kept at a low level.

Abstract: An illumination system (1) comprises a plurality of light source assemblies (10) and a common controller (21). Each light source assembly (10) comprises a plurality of individually controllable light sources (11, 12, 13) for generating light of mutually different colors. The controller is designed to generate a plurality of switched frequency signals (SF1, SF2, SF3) for the respective light sources, with a frequency within a relatively small frequency band, the different frequency signals (SF1, SF2, SF3) having mutually different frequencies (f1, f2, f3). In each light source assembly, each light source is responsive to a respective one of said switched frequency signals (SF1, SF2, SF3), the light source being ON for as long as the respective switched frequency signal is zero and being OFF for as long as the respective switched frequency signal has the respective frequency.

Abstract: An illumination system (1) comprises a plurality of light source assemblies (10) and a common controller (21). Each light source assembly (10) comprises a plurality of individually controllable light sources (11, 12, 13) for generating light of mutually different colors. The controller is designed to generate a plurality of switched frequency signals (SF1, SF2, SF3) for the respective light sources, with a frequency within a relatively small frequency band, the different frequency signals (SF1, SF2, SF3) having mutually different frequencies (f1, f2, f3). In each light source assembly, each light source is responsive to a respective one of said switched frequency signals (SF1, SF2, SF3), the light source being ON for as long as the respective switched frequency signal is zero and being OFF for as long as the respective switched frequency signal has the respective frequency.

Abstract: A drive circuit (1) for driving a load (3) comprises: a switched mode power supply (10) for supplying at the output (2a, 2b) a switched output current (IL); a controller (20) for controlling the power supply; a current sensor (15) for generating a current sense signal (Vi 5) representing the output current (IL); a voltage sensor (30) for generating a voltage sense signal (Sy) rep->resenting the output voltage (Vp; Vp+Vis) of the circuit. The controller receives the current sense signal, and generates a switching time control signal (Sc) for the switched mode power supply (10) on the basis of the current sense signal. The controller further receives the voltage sense signal. In response to a change in the voltage sense signal, the controller changes the switching time control signal such as to effectively compensate an effect of the output voltage change on the average value of the output current.

Abstract: A switched mode power supply assembly (1) is described, comprising at least two switched mode power supply units (10i) coupled to each other in parallel; each power supply unit (10i) having an output stage (50i, 60i) capable of selectively operating in a first mode wherein its output signal (IOUT,I) is increasing and operating in a second mode wherein its output signal (IOUT,i) is decreasing; a control device (100) receiving mode switch control signals from all power supply units (10i); wherein the control device (100), if it finds that the actual phase relationship between two power supply units deviates from an optimal phase relationship, is designed to generate synchronising control signals for at least one power supply unit (102), effectively changing the timing of at least one mode switch moment, such that the deviation between the actual phase relationship and said optimal phase relationship is reduced.

Abstract: The present invention relates to a multiple LED driver circuit in which each LED (15, 17) is controlled by a bypass switch (19, 21). The LEDs are supplied by a switched mode power supply (8) and are connected to a constant current source to draw a predetermined current through the LEDs. The switched mode power supply is arranged to output different voltages depending on the number of switched-on LEDs. This is carried out by supplying the control signals (sw1, sw2) of the bypass switches to the switched mode power supply. In this way, the power dissipation of the constant current source can be kept at a low level.

Abstract: The present invention relates to a device for determining characteristics of a lighting unit, comprising at least two flux sensor each having different wavelength characteristics and being arranged to measure light emitted from the lighting unit, yielding two measurements, and means for calculating a dominant wavelength and a real flux for the lighting unit based on the measurements and the sensors' wavelength characteristics. The present invention provides for a direct calculation of dominant wavelength and real flux without the need for predefined data about the light source or without performing additional measurements such as using temperature measurements. The present invention also relates to a system using such a device, and a corresponding method for determining characteristics of a lighting unit.

Abstract: A switched mode power supply assembly that has a plurality of power supply modules cyclically coupled to each other. Each power supply module has a synchronization control module for generating a synchronization control signal for a next neighboring module and for receiving a synchronization control signal from a previous neighboring module to ensure interleaved operation of all modules.