Methods and systems for maintaining the illumination intensity of light emitting diodes

1. A circuit comprising:

a voltage source;

a light-emitting diode (LED) having a desired minimal intensity level associated therewith, the desired minimal intensity level being correlated to a pre-defined LED set-point temperature;

a thermal sensor in proximity to the LED and adapted to sense a temperature proximal to the LED;

wherein, responsive to a sensed temperature greater than the pre-defined LED set-point temperature, current supplied to the LED is increased in a step-wise manner from an original current level to an increased current level; and

wherein, responsive to a sensed temperature less than a second pre-defined LED temperature, current supplied to the LED is decreased in a step-wise manner from the increased current level to the original current level, the second pre-defined LED temperature being less that the pre-defined LED set-point temperature.

2. The circuit of claim 1 , wherein:

the thermal sensor comprises a switch adapted to activate responsive to the pre-defined LED set-point temperature being exceeded.

3. The circuit of claim 1 , wherein the thermal sensor comprises a resistor programmable SOT temperature switch.

4. The circuit of claim 1 , wherein the thermal sensor is positioned adjacent an LED junction of the LED.

5. The circuit of claim 1 , wherein the thermal sensor senses an LED-junction temperature.

6. The circuit of claim 1 , wherein the circuit comprises a plurality of LEDs.

7. The circuit of claim 6 , wherein the thermal sensor is positioned in proximity to the plurality of LEDs and senses a temperature proximal to the plurality of LEDs.

8. The circuit of claim 6 , comprising:

a plurality of thermal sensors; and

wherein each of the plurality of thermal sensors is positioned in proximity to an LED of the plurality of LEDs and senses a temperature proximal to the LED.

9. The circuit of claim 1 , wherein the voltage source is a battery.

10. The circuit of claim 1 , comprising a current regulator.

11. A method comprising:

sensing, via a thermal sensor, a temperature proximal to an LED;

determining whether a sensed temperature exceeds a pre-defined set-point temperature that correlates to a minimal intensity level of the LED;

responsive to a determination that the sensed temperature exceeds the pre-defined set-point temperature,

increasing, in a step-wise manner, current level applied to the LED from a nominal level to an increased current level; and

responsive to a determination that the sensed temperature is less than a second pre-defined temperature,

decreasing, in a step-wise manner, current level applied to the LED from the increased current level to the nominal current level.

12. The method of claim 11 , wherein the steps of claim 11 are repeated if the sensed temperature is determined to be not greater than the pre-defined set-point temperature.

13. The method of claim 11 , wherein the increasing-current step causes an LED illumination intensity to be not less than the minimal intensity level.

14. The method of claim 11 , wherein an increased current is in the range of about 260 mA to about 330 mA.

15. The method of claim 11 , wherein the increasing-current step comprises increasing a voltage supplied a voltage source of a circuit associated with the LED.

16. The method of claim 11 , wherein the increasing-current step comprises decreasing a resistance of a circuit associated with the LED.

17. The method of claim 11 , wherein the sensing step comprises the thermal sensor sensing an LED junction temperature.

18. The method of claim 11 , wherein the determining step is performed by the thermal sensor.