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1. WO2007003006 - A MULTICOLOUR LED LIGHTING CIRCUIT

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CLAIMS

1 . A lighting circuit including:
a plurality of voltage reference sources;
a plurality of power supply controllers, each of which is connected to a respective voltage reference source;
a plurality of LED loads, each of which is supplied with power from a respective one of the power supply controllers;
wherein each LED load is for emitting a different colour selected from at least two different colours, the LED loads being arranged together such that their respective outputs are additive to give a colour output from the plurality of LED loads;
wherein each voltage reference source operates its power supply controller independently of the others to control the supply of a substantially constant direct current to its LED load to provide a preselected light intensity output such that the plurality of LED loads together provide a particular colour output, each voltage reference source also being variable for the power supply controllers to vary, respectively, the direct current to each LED load to thereby independently vary the light intensity output from each LED load and thus change the colour output from the plurality of LED loads.

2. A lighting circuit as claimed in claim 1 wherein each power supply controller includes a feedback circuit in which a signal representative of the direct current is fed back for the power supply controller to maintain the direct current substantially at a level which is set via a reference voltage from its voltage reference source.

3. A lighting circuit as claimed in claim 1 or claim 2 wherein the plurality of voltage reference sources are provided by a microprocessor.

4. A lighting circuit as claimed in claim 3 wherein the microprocessor is programmable to include, for each LED load, data that represents the minimum direct current that provides a light output from the LED load and the maximum direct current that the LED load can draw, and wherein the microprocessor is programmable to provide a reference voltage to operate each power supply controller such that the direct current supplied to its LED load does not exceed said maximum.

5. A lighting circuit as claimed in claim 3 or claim 4 including a white light balance circuit for sensing the colour output from the plurality of LED loads and which provides signals to the microprocessor for determining reference voltages for the direct current supplied to each LED load for the LED loads to provide a white light output at their minimum output intensities and the direct current supplied to each LED load for the LED loads to provide a white light output at their maximum output intensities.

6. A lighting circuit as claimed in any one of claims 1 to 5 wherein each power supply controller includes a switching section operatable via voltage reference signals from the voltage reference sources for switching a supply of dc power through a smoothing filter section.

7. A lighting circuit as claimed in any one of claims 1 to 5 wherein each power supply controller includes a control section for providing a control signal in dependence upon voltage reference signals from the voltage reference sources, and a current regulation section for receiving the control signal to thereby regulate a direct current drawn from a dc power source.

8. A lighting circuit as claimed in claim 7 wherein the control section and the current regulation section of each power supply controller are spatially separated whereby each current regulation section is located in proximity to the LED loads.

9. A lighting system as claimed in any one of claims 1 to 8 wherein the LED loads include at least two of a load of red LED's, a load of green LED's and a load of blue LED's.

10. A lighting system including:
a system controller;

a plurality of lighting circuits as claimed in any one of claims 1 to 7;
wherein the system controller is connected to control the voltage reference sources of each lighting circuit.

1 1 . A lighting system as claimed in claim 10 wherein the plurality of voltage reference sources and plurality of power supply controllers of each lighting circuit are provided as a module which is interchangeable with other such modules.

12. A lighting system as claimed in claim 10 or claim 1 1 wherein the plurality of voltage reference sources are provided by a microprocessor.

13. A lighting system as claimed in claim 1 1 wherein differently sized and/or differently configured LED loads are connectable to each interchangeable module.

14. A lighting system as claimed in claim 1 1 wherein each interchangeable module includes a white light balance circuit (as specified in claim 4).

15. A lighting system including:
a system controller;
a plurality of lighting circuits as claimed in claim 8;
wherein the system controller is connected to control the voltage reference sources of each lighting circuit;
wherein the current regulation section of each power supply controller and the plurality of LED loads are provided as a module which is interchangeable with other such modules.