System having independent control of circadian response and color temperature

1. A lighting fixture configured to produce a cumulative light output comprising a color temperature, an intensity, and a circadian response, the lighting fixture comprising:

a first set of light sources including a first light source configured to emit light having a first color temperature and a second light source configured to emit light having a second color temperature;

wherein the first and second color temperatures comprise a substantially same warm color temperature in the range of 1800K-3000K; and

wherein the light emitted by the first light source is configured to produce a higher spectral power distribution over a range of wavelengths in a first region of the visible light spectrum than that of the second light source over the range of wavelengths in the first region of the visible light spectrum;

a second set of light sources including s a third light source configured to emit light having a third color temperature and a fourth light source configured to emit light having a fourth color temperature;

wherein the third and fourth color temperatures comprise a substantially cool color temperature in the range of 3500K-8000K; and

wherein the third light source is configured to produce a higher spectral power distribution over the range of wavelengths in the first region of the visible light spectrum than that of the fourth light source over the range of wavelengths in the first region of the visible light spectrum;

a communication circuit configured to receive commands; and

a control circuit coupled to the communication circuit, the control circuit configured to:

receive, via the communication circuit, a command to adjust the circadian response of the cumulative light output, wherein the circadian response comprises a value that indicates a sum of respective intensities of the first and third light sources with respect to a sum of respective intensities of the first, second, third, and fourth light sources representing the cumulative light output of the lighting fixture;

based on the command, determine a respective intensity of the first light source, the second light source, the third light source, and the fourth light source; and

control the first, second, third, and fourth light sources to the determined respective intensities to produce the adjusted circadian response of the cumulative light output.

2. The lighting fixture of claim 1 , wherein the first region of the visible light spectrum comprises a blue region of the visible light spectrum.

3. The lighting fixture of claim 2 , wherein the range of wavelengths is approximately 425 nanometers to 525 nanometers.

4. The lighting fixture of claim 1 , wherein the first light source comprises a blue light emitting diode (LED and the second light source comprises a purple LED.

5. The lighting fixture of claim 4 , wherein the blue LED has a primary emission peak between approximately 425 nanometers to 525 nanometers, further wherein the purple LED has a primary emission peak less than 425 nanometers.

6. The lighting fixture of claim 4 , wherein the blue LED has a primary emission peak between approximately 440 nanometers to 490 nanometers, further wherein the purple LED has a primary emission peak less than 425 nanometers.

7. The lighting fixture of claim 1 , wherein the third light source comprises a blue light emitting diode (LED and the fourth light source comprises a purple LED.

8. The lighting fixture of claim 7 , wherein the blue LED has a primary emission peak between approximately 425 nanometers to 525 nanometers, further wherein the purple LED has a primary emission peak less than 425 nanometers.

9. The lighting fixture of claim 8 , wherein the blue LED has a primary emission peak between approximately 440 nanometers to 490 nanometers, further wherein the purple LED has a primary emission peak less than 425 nanometers.

10. The lighting fixture of claim 1 , wherein the first color temperature and the second color temperature have corresponding chromaticities within a one-step MacAdam ellipse of each other.

11. The lighting fixture of claim 10 , wherein the second third color temperature and the fourth color temperature have corresponding chromaticities within a one-step MacAdam ellipse of each other.

12. The lighting fixture of claim 1 , wherein the control circuit is further configured to maintain the intensity and the color temperature of the cumulative light output when the circadian response is adjusted in response to the received command.

13. The lighting fixture of claim 1 , wherein the control circuit is further configured to:

receive a second command comprising an intensity, a correlated color temperature (CCT), and a circadian response;

determine intensities of the first, second, third, and fourth light sources based on the received intensity, CCT, and circadian response of the second command, wherein the determined intensity of the first light source as a percentage of the first and second light sources is equal to the determined intensity of the third light source as a percentage of the third and fourth light sources; and

control the intensities of the first, second, third, and fourth light sources to produce the intensity, CCT, and circadian response of the cumulative light output according to the received second command.

14. A system for controlling a cumulative light output, the system comprising:

a first set of light sources including a first light emitting diode (LED) having a primary emission peak between a range of 425 nanometers to 525 nanometers and configured to emit light having a first color temperature and a second LED having a primary emission peak less than 425 nanometers and configured to emit lighting having a second color temperature;

wherein the first and second color temperatures comprise a first substantially same color temperature in the range of 1800K-3000K; and

wherein the light emitted by the first LED is configured to produce a higher spectral power distribution over the range of 425 nanometers to 525 nanometers than that of the second LED over the range of 425 nanometers to 525 nanometers; and

a second set of light sources including a third LED having a primary emission peak between the range of 425 nanometers to 525 nanometers and configured to emit light having a third color temperature and a fourth LED having a primary emission peak less than 425 nanometers and configured to emit light having a fourth color temperature;

wherein the third and fourth color temperatures comprise a second substantially same color temperature in the range of 3500K-8000K; and

wherein the light emitted by the third LED is configured to produce a higher spectral power distribution over the range of 425 nanometers to 525 nanometers than that of the fourth LED over the range of 425 nanometers to 525 nanometers.

15. The system of claim 14 , wherein the first, second, third, and fourth LEDS are housed within a lighting fixture.

16. The system of claim 15 , wherein the first color temperature and the second color temperature have corresponding chromaticities within a one-step MacAdam ellipse of each other; and

wherein the third color temperature and the fourth color temperature have corresponding chromaticities within a one-step MacAdam ellipse of each other.

17. The system of claim 16 , further comprising:

an input device; and

a system controller comprising a communication circuit for transmitting and receiving commands, wherein the system controller is configured to:

receive, via the communication circuit, a command from the input device to adjust a circadian response, wherein the circadian response comprises a value that indicates a sum of respective intensities of the first and third LEDs with respect to a sum of respective intensities of the first, second, third, and fourth LEDs representing the cumulative light output of the lighting fixture; and

based on the received command, transmit, via the communication circuit, a second command to adjust the circadian response to the lighting fixture.

18. The system of claim 17 , wherein the lighting fixture further comprises:

a communication circuit configured to receive commands from the system controller; and

a control circuit coupled to the communication circuit of the lighting fixture and operably coupled to the first, second, third, and fourth LEDs, wherein the control circuit is configured to:

receive, via the communication circuit of the lighting fixture, the second command to adjust the circadian response of the cumulative light output of the lighting fixture;

based on the received second command, determine a respective intensity of the first, second, third, and fourth LEDs; and

control the first, second, third and fourth LEDs to the determined respective intensities to produce the adjusted circadian response of the cumulative light output of the lighting fixture.