Digitally controlled current regulator for high power solid state lighting
View Patent ↗A representative apparatus embodiment provides for controlling current supplied to solid state lighting, such as light emitting diodes. A representative apparatus comprises a memory adapted to store a plurality of current parameters, and a control circuit adapted to modulate an energizing cycle time period for providing a substantially constant DC average current to the solid state lighting in response to a selected current parameter from the plurality of current parameters. In a representative embodiment, the control circuit modulates a current provided to the solid state lighting in response to a predetermined minimum current level (I MIN ) parameter and a predetermined peak current level (I P ) parameter, such that the DC average current level (I O ) is substantially proportional to one-half of a sum of a predetermined peak current level (I P ) and a predetermined minimum current level I MIN ( I O ∝ I P + I MI N 2 ) .
1. A method of providing power to a solid state lighting system, the method comprising:
starting an energizing cycle by providing current through an inductor coupled to the solid state lighting system;
monitoring the inductor current level;
reducing the inductor current level when a predetermined peak inductor current level is reached; and
commencing a next energizing cycle by increasing the inductor current level when a predetermined minimum inductor current level is reached.
2. The method of claim 1 , wherein the predetermined minimum current level (I MIN ) is substantially close to zero.
3. The method of claim 1 , further comprising:
determining the inductor current by measuring a first corresponding voltage; and
comparing the first corresponding voltage to a first predetermined reference voltage to determine when the predetermined peak inductor current level is reached.
4. The method of claim 1 , further comprising:
determining the inductor current by measuring a second corresponding voltage; and
comparing the second corresponding voltage to a second predetermined reference voltage to determine when the predetermined minimum inductor current level is reached.
5. The method of claim 1 , further comprising:
providing a substantially constant DC average current by maintaining substantially constant a predetermined peak current level (I P ) and a predetermined minimum current level (I MIN ).
6. The method of claim 5 , wherein the DC average current level (I O ) is substantially equal to one-half of a sum of the predetermined peak current level (I P ) and the predetermined minimum current level
I
MI
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.
7. The method of claim 5 , wherein the DC average current level (I O ) is substantially proportional to one-half of a sum of a predetermined peak current level (I P ) and a predetermined minimum current level
I
MI
N
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I
O
∝
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P
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8. A computer-readable storage medium having instructions stored thereon that, in response to execution by at least one computing device, cause the at least one computing device to:
start an energizing cycle by providing current through an inductor coupled to a solid state lighting system;
monitor the inductor current level;
reduce the inductor current level when a predetermined peak inductor current level is reached; and
commence a next energizing cycle when a predetermined minimum current level is reached.
9. The computer-readable storage medium of claim 8 , wherein the predetermined minimum current level (I MIN ) is substantially close to zero.
10. The computer-readable storage medium of claim 8 , wherein the instructions, in response to execution, further cause the at least one computing device to:
determine the inductor current by measuring a first corresponding voltage; and
compare the first corresponding voltage to a first predetermined reference voltage to determine when the predetermined peak inductor current level is reached.
11. The computer-readable storage medium of claim 8 , wherein the instructions, in response to execution, further cause the at least one computing device to:
determine the inductor current by measuring a second corresponding voltage; and
compare the second corresponding voltage to a second predetermined reference voltage to determine when the predetermined minimum inductor current level is reached.
12. The computer-readable storage medium of claim 8 , wherein the instructions, in response to execution, further cause the at least one computing device to provide a substantially constant DC average current by maintaining substantially constant a predetermined peak current level (I P ) and a predetermined minimum current level (I MIN ).
13. The computer-readable storage medium of claim 12 , wherein the DC average current level (I O ) is substantially equal to one-half of a sum of the predetermined peak current level (I P ) and the predetermined minimum current level
I
MI
N
(
I
O
≈
I
P
+
I
M
I
N
2
)
.
14. The computer-readable storage medium of claim 12 , wherein the DC average current level (I O ) is substantially proportional to one-half of a sum of a predetermined peak current level (I P ) and a predetermined minimum current level
I
MI
N
(
I
O
∝
I
P
+
I
MI
N
2
)
.