Intelligent light degradation sensing LED traffic signal

• US 7,425,798 B2
• Filed: 03/30/2005
• Issued: 09/16/2008
• Est. Priority Date: 01/23/2003
• Status: Expired due to Term

• Current Assignee: Current Lighting Solutions, LLC (f/k/a GE Lighting Solutions, LLC) (American Industrial Partners)
• Original Assignee: Lumination LLC
• Inventors: St.-Germain, Nicolas
• Primary Examiner(s): Lee; Wilson
• Assistant Examiner(s): VY, HUNG T
• Application Number:
  US11/093,391
• Publication Number:
  US 20050206529A1
• Time in Patent Office: 1,266 Days
• Field of Search: 340/815.45, 340/907, 315/191, 315/362, 315/129, 315/130, 315/131, 315/134, 315/291, 315/119, 372/31
• US Class Current: 315/129
• CPC Class Codes: B61L 2207/02 using light-emitting diodes [LEDs]
• CPC Class Codes: B61L 5/1881 Wiring diagrams for power supply, control or testing
• CPC Class Codes: G08G 1/095 Traffic lights
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 45/12 using optical feedback
• CPC Class Codes: H05B 45/14 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/18 using temperature feedback
• CPC Class Codes: H05B 45/58 involving end of life detection of LEDs
• CPC Class Codes: H05B 47/20 Responsive to malfunctions or to light source life; for protection
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

The inventive signal incorporates an intelligent diagnosis module inside a light emitting diode (LED) signal, such as an LED traffic signal. The inventive signal can self-extinguish or send a signal through its communication port at the end of its useful life when the LEDs are no longer providing the required light output. Additionally, the inventive signal sends a signal to increase the current as the LEDs degrade to ensure the light output is above a threshold minimum.

Claims

1. A method of controlling a LED signal comprising the steps of:

receiving LED data for one or more LEDs;

generating a control signal in response to the LED data, wherein the LED data are, a light output, an average ambient temperature, and hours of operation of the LED array, and the control signal is an End of Life signal, wherein the End of Life signal is utilized to indicate end of life for at least one of the one or more LEDs; and

calculating a maximum number of hours wherein said maximum number of hours is proportional to the average ambient temperature, comparing the hours of operation to the maximum number of hours, comparing the light output to a light output minimum, wherein if the light output is below the light output minimum and/or hours of operation is greater than the maximum number of hours generating the End of Life signal and if the light output is not below the light output minimum and/or the hours of operation are not greater than the maximum number of hours, incrementing a counter to continue sampling the light output and the hours of operation at a predefined interval.

2. The method of controlling a LED signal of claim 1, further comprising the steps of measuring the ambient temperature using a temperature sample rate and calculating an average ambient temperature.

3. The method of controlling a LED signal of claim 1, further comprising the steps of measuring the input voltage using a voltage sample rate and calculating an average input voltage.

4. The method of controlling a LED signal of claim 3, further comprising the steps of comparing the input voltage to a reference voltage and generating a turn-off signal if the input voltage is below the reference voltage.

5. The method of controlling a LED signal of claim 4, further comprising the step of turning off the signal in response to the turn-off signal.

6. The method of controlling a LED signal of claim 1, further comprising the step of measuring the output current using a current sample rate.

7. The method of controlling a LED signal of claim 6, further comprising the step of measuring the light output using a light output sample rate.

8. The method of controlling a LED signal of claim 7, further comprising the steps comparing the light output to a light output minimum and comparing the current to a current maximum, and if the light output is below the light output minimum and the output current is below the current maximum generating the current adjust signal.

9. The method of controlling a LED signal of claim 8, further comprising the step of increasing the output current in response to the current adjust signal.

10. The method of controlling a LED signal of claim 9, further comprising the steps of measuring the light output using a light output sample rate and timing the hours of operation.

11. The method of controlling a LED signal of claim 1, further comprising the step of measuring the light output using a light output sample rate.

12. The method of controlling a LED signal of claim 1, further comprising the step of timing the hours of operation.

13. The method of controlling a LED signal of claim 1, further comprising the steps communicating the End of Life signal to a receiver or turning-off the signal in response to the End of Life signal.

14. A method of controlling a LED signal comprising the steps of:

receiving LED data, said LED data are voltage, ambient temperature, output current, light output, average input voltage, average ambient temperature, hours of operation of the LED array, and/or lamp ID and the control signal is an End of Life signal, wherein the End of Life signal is utilized to indicate end of life for at least one of the one or more LEDs;

generating a control signal in response to the LED data;

measuring the ambient temperature using a temperature sample rate;

calculating the average ambient temperature;

measuring the input voltage using a voltage sample rate;

calculating the average input voltage;

measuring the output current using a current sample rate;

measuring the light output using a light output sample rate;

timing the hours of operation;

comparing the input voltage to a reference voltage and generating a turn-off signal if the input voltage is below the reference voltage;

comparing the light output to a light output minimum, comparing the current to a current maximum, and if the light output is below the light output minimum and the output current is below the current maximum generating a current adjust signal and increasing the output current in response to the current adjust signal; and

calculating a maximum number of hours, said maximum number of hours is proportional to the average ambient temperature, comparing the hours of operation to the maximum number of hours, comparing the light output to a light output minimum, wherein if the light output is below the light output minimum and/or hours of operation is greater than the maximum number of hours generating the End of Life signal and if the light output is not below the light output minimum and/or the hours of operation are not greater than the maximum number of hours, incrementing a counter to continue sampling the light output and the hours of operation at a predefined interval.

15. The method of controlling a LED signal of claim 14, further comprising the step of turning off the signal in response to the turn-off signal.

16. The method of controlling a LED signal of claim 14, further comprising the steps communicating the End of Life signal to a receiver or turning-off the signal in response to the End of Life signal.

17. The method of controlling a LED signal of claim 14, further comprising the step of saving the LED data to memory.

18. The method of controlling a LED signal of claim 14, wherein the current sample rate is predetermined and the light output sample rate is predetermined.

19. The method of controlling a LED signal of claim 14, wherein an output current adjust and end of life calculation are performed every time the output current and light output are sampled.

20. The method of controlling a LED signal of claim 14, wherein the current sample rate is predetermined, the light output sample rate is predetermined and an output current adjust and end of life calculation are performed every time the output current and light output are sampled.

21. The method of controlling a LED signal of claim 14, further comprising the step of communicating at least one LED data or at least one control signal to a receiver.

22. The method of controlling a LED signal of claim 14, wherein the voltage sample rate is at least one measurement every 1 ms and the temperature sample rate is at least one measurement every 100 ms.

23. The method of controlling a LED signal of claim 22, wherein the current sample rate is every 168 hours of operation, the light output sample rate is every 168 hours of operation and an output current adjust and end of life calculation are performed every time the output current and light output are sampled.