Multi-segment LED lighting apparatus configurations
View Patent ↗A solid state lighting apparatus can include a Light Emitting Diode (LED) string that includes a plurality of light emitting diode (LED) segments that are coupled in series with one another wherein a ratio of respective numbers of LEDs in each of the segments is about equal to a ratio of respective average powers for each of the respective segments. Other configurations are also disclosed.
1. A solid state lighting apparatus comprising:
a Light Emitting Diode (LED) string including a plurality of light emitting diode (LED) segments coupled in series with one another wherein a ratio of respective lumen output from each of the segments, being provided by a respective total epi-area for each of the segments, is about equal to a ratio of respective average powers for each of the respective segments;
wherein a ratio of respective numbers of LEDs in each of the segments is about equal to the ratio of the respective average powers for each of the respective segments; and
wherein a first-on/last-off segment included in the plurality of segments includes LEDs having highest efficacy of all LEDs in the string and a last-on/first-off segment included in the plurality of segments includes LEDs having lowest efficacy of all LEDs in the string.
2. The apparatus of claim 1 wherein the LEDs included in each of the segments are identical.
3. The apparatus of claim 1 wherein the respective number of LEDs in each of the segments are coupled together in parallel where the respective number is greater than 1.
4. The apparatus of claim 1 wherein the string includes 3 segments having equal forward voltages and a ratio of currents for respective utilizations of the segments of 1:2:3, wherein a ratio of respective efficacies of LEDs in each of the segments is 3 for a first-on/last-off segment, 2 for an intermediate segment, and 1 for a last-on/first-off segment.
5. The apparatus of claim 1 wherein the string includes 3 segments wherein the ratio of respective average powers in each of the segments is 17 for a first-on/last-off segment, 15 for an intermediate segment, and 9 for a last-on/first-off segment.
6. The apparatus of claim 1 wherein the ratio of respective numbers of LEDs in each of the segments comprises 3 in a first-on/last-off segment, 2 in an intermediate segment, and 1 for a last-on/first-off segment.
7. The apparatus of claim 1 further comprising:
a rectifier circuit housed in the solid state lighting apparatus, coupled to an ac voltage source configured to provide a rectified ac voltage; and
a driver circuit, coupled to the rectifier circuit and configured to provide current to the string.
8. The apparatus of claim 1 wherein the driver circuit further comprises:
a plurality of current diversion circuits, respective ones of which are coupled in parallel with respective segments and configured to operate responsive to bias state transitions of the respective segments.
9. A solid state lighting apparatus comprising:
a Light Emitting Diode (LED) string including a plurality of light emitting diode (LED) segments coupled in series with one another, wherein a first-on/last-off segment included in the plurality of segments includes LEDs having highest efficacy of all LEDs in the string and a last-on/first-off segment included in the plurality of segments includes LEDs having lowest efficacy of all LEDs in the string.
10. The apparatus of claim 9 wherein a ratio of respective numbers of LEDs in each of the segments is about equal to a ratio of respective average powers for each of the respective segments.
11. The apparatus of claim 9 wherein a respective number of LEDs in each of the segments are coupled together in parallel where the respective number is greater than 1.
12. The apparatus of claim 9 wherein the string includes 3 segments wherein a ratio of respective efficacies of LEDs in each of the segments is 3 for the first-on/last-off segment, 2 for an intermediate segment, and 1 for the last-on/first-off segment.
13. The apparatus of claim 9 wherein the string includes 3 segments and a ratio of respective average powers in each of the segments is 17 for a first-on/last-off segment, 15 for an intermediate segment, and 9 for a last-on/first-off segment.
14. The apparatus of claim 9 wherein the string includes 3 segments and a ratio of respective numbers of LEDs in each of the segments comprises 3 in the first-on/last-off segment, 2 in an intermediate segment, and 1 for the last-on/first-off segment.
15. The apparatus of claim 9 further comprising:
a rectifier circuit housed in the solid state lighting apparatus, coupled to an ac voltage source configured to provide a rectified ac voltage; and
a driver circuit, coupled to the rectifier circuit and configured to provide current to the string.
16. The apparatus of claim 15 wherein the driver circuit further comprises:
a plurality of current diversion circuits, respective ones of which are coupled in parallel with respective segments and configured to operate responsive to bias state transitions of the respective segments.
17. A solid state lighting apparatus comprising:
a Light Emitting Diode (LED) string including a plurality of light emitting diode (LED) segments coupled in series with one another, wherein a ratio of respective numbers of LEDs in each of the segments is about equal to a ratio of respective average powers for each of the respective segments and a first-on/last-off segment included in the plurality of segments includes highest efficacy LEDs in the string and a last-on/first-off segment included in the plurality of segments includes lowest efficacy LEDs in the string.
18. The apparatus of claim 17 wherein the string includes 3 segments each having equal forward bias voltages, a ratio of respective efficacies of LEDs in the segments is: 3 for the first-on/last-off segment, 2 for an intermediate segment, and 1 for the last-on/first-off segment.
19. The apparatus of claim 17 wherein the string includes 3 segments and a ratio of respective average powers in each of the segments is 17 for the first-on/last-off segment, 15 for an intermediate segment, and 9 for the last-on/first-off segment.
20. The apparatus of claim 17 wherein the string includes 3 segments and a ratio of respective numbers of LEDs in each of the segments comprises 3 in the first-on/last-off segment, 2 in an intermediate segment, and 1 for the last-on/first-off segment.
21. The apparatus of claim 17 further comprising:
a rectifier circuit housed in the solid state lighting apparatus, coupled to an ac voltage source configured to provide a rectified ac voltage; and
a driver circuit, coupled to the rectifier circuit and configured to provide current to the string.
22. The apparatus of claim 21 wherein the driver circuit further comprises:
a plurality of current diversion circuits, respective ones of which are coupled in parallel with respective segments and configured to operate responsive to bias state transitions of the respective segments.