Supplemental load circuit for low power traffic lamps

1. A supplemental load circuit configured to provide a supplemental power consumption to enable a lamp unit operating at a low power consumption to operate with a traffic controller configured to test for a higher power consumption, the supplemental load circuit comprising:

a load;

power input circuitry configured to receive a DC power signal from the lamp unit; and

a control switch configured to receive a control signal having a duty cycle from the lamp unit;

wherein the control switch is configured to control application of the DC power signal to the load by the power input circuitry based on the duty cycle of the control signal to provide the higher power consumption for which the traffic controller is configured to test.

2. A supplemental load circuit as in claim 1 , wherein the control switch comprises:

a first position permitting application of the DC power signal to the load by the power input circuitry; and

a second position discontinuing application of the DC power signal to the load by the power input circuitry;

wherein the control switch actuates between the first position and the second position based on the duty cycle of the control signal.

3. A supplemental load circuit as in claim 1 , wherein the duty cycle of the control signal corresponds to a pulse width of the control signal and the control switch is configured such that the DC power signal is applied to the load for the duration of the pulse width.

4. A supplemental load circuit as in claim 3 , wherein application of the DC power signal to the load for the duration of the pulse width provides the supplemental power consumption, the supplemental power consumption being sufficient to enable the lamp unit to operate with the traffic controller.

5. A supplemental load circuit as in claim 3 , wherein:

the lamp unit operates at a first power consumption and the traffic controller is configured to test for a second power consumption, the second power consumption being greater than the first power consumption; and

application of the DC power signal to the load for the duration of the pulse width provides the supplemental power consumption, the supplemental power consumption being greater than or equal to the second power consumption minus the first power consumption.

6. A supplemental load circuit as in claim 3 , wherein the pulse width of the control signal is synchronized with an external AC power signal received by the lamp unit.

7. A supplemental load circuit as in claim 1 , wherein the load is connected in parallel with a light emitting diode engine included in the lamp unit.

8. A traffic lamp operating at a low power consumption and controlled by a traffic controller configured to test for higher power consumption comprising:

a power converter configured to convert an externally supplied AC power signal into a DC power signal;

a lamp load, the lamp load being powered by the DC power signal;

a supplemental load;

a control command circuit configured to generate a control signal having a duty cycle; and

a control switch configured to control application of the DC power signal to the supplemental load based on the duty cycle of the control signal to provide the higher power consumption for which the traffic controller is configured to test.

9. A traffic lamp as in claim 8 , wherein application of the DC power signal to the supplemental load based on the duty cycle of the control signal provides a supplemental power consumption sufficient to allow the traffic lamp to operate with a traffic controller configured to test for a total power consumption, the total power consumption being greater than a lamp power consumption associated with the lamp load.

10. A traffic lamp as in claim 8 , wherein the control command circuit is configured to generate the control signal based on a desired supplemental power consumption, the desired supplemental power consumption being based on a total power consumption required by a traffic controller and a lamp power consumption associated with the lamp load.

11. A traffic lamp as in claim 10 , wherein:

the duty cycle of the control signal corresponds to a pulse width of the control signal;

the control switch is configured such that the DC power signal is applied to the supplemental load for the duration of the pulse width of the control signal; and

application of the DC power signal to the supplemental load for the duration of the pulse width provides a supplemental power consumption greater than or equal to the desired supplemental power consumption.

12. A traffic lamp as in claim 11 , wherein the desired supplemental power consumption equals the difference between the total power consumption and the lamp power consumption.

13. A traffic lamp as in claim 8 , wherein the control command circuit generates the control signal based on a plurality of pre-programmed parameters.

14. A traffic lamp as in claim 13 , wherein the plurality of pre-programmed parameters comprise:

a pulse width; and

a pulse frequency.

15. A traffic lamp as in claim 14 , wherein the pulse frequency corresponds to the frequency of the externally supplied AC power signal.

16. A traffic lamp as in claim 8 , wherein the lamp load comprises a light emitting diode engine and the supplemental load is connected in parallel with the light emitting diode engine.

17. A method for enabling a lamp unit operating at a low power consumption to operate with a traffic controller configured to test for a higher power consumption, the method comprising:

receiving, at a control switch included in a supplemental load circuit, a control signal having a duty cycle;

receiving, at the supplemental load circuit, a DC power signal from a power converter included in the lamp unit; and

applying the DC power signal, using the control switch, to a supplemental load included in the supplemental load circuit based on the duty cycle of the control signal such that the lamp unit operates with the traffic controller and provides the higher power for which the traffic controller is configured to test.

18. A method as in claim 17 , further comprising:

converting, at the power converter, an externally supplied AC power signal into the DC power signal;

supplying the DC power signal from the power converter to the supplemental load circuit; and

supplying the DC power signal from the power converter to a lamp load included in the lamp unit.

19. A method as in claim 17 , further comprising generating, with a control command circuit included in the lamp unit, the control signal having the duty cycle based on a plurality of pre-programmed parameters, the pre-programmed parameters including a pulse width and a pulse frequency.

20. A method as in claim 17 , wherein the duty cycle of the control signal corresponds to a pulse width of the control signal and applying the DC power signal, using the control switch, to the supplemental load included in the supplemental load circuit based on the duty cycle of the control signal comprises applying the DC power signal, using the control switch, to the supplemental load for the duration of the pulse width of the control signal.