Fast reignition of a high intensity discharge lamp

1. An apparatus for a fast reignition of a high intensity discharge lamp comprising:

a ballast operatively coupled to said lamp, and configured to receive power from a power supply;

a timer circuit configured to enter a timing phase and produce a quantum of timing information when said lamp ceases to receive power from said power supply; and

a control circuit configured to receive said quantum of timing information and permit said ballast to restrike said lamp based on said quantum of timing information;

wherein said timer circuit is powered internally during said timing phase;

wherein said timer circuit further comprises a resistive-capacitive circuit configured to be charged by said power supply when said lamp is receiving power from said power supply, to discharge when said timer circuit is in said timing phase, and to output a timer voltage; and

wherein said control circuit is configured to permit said ballast to restrike said lamp when said timer voltage drops below a predetermined level which indicates that a cool-down period of said lamp has elapsed.

2. The apparatus of claim 1 , wherein said timer circuit further comprises:

a clock circuit configured to run when said lamp ceases to receive power from said power supply and to initialize when said lamp is ignited; and

a battery configured to power said clock circuit when said lamp ceases to receive power from said power supply.

3. The apparatus of claim 2 , wherein said control circuit is configured to permit said ballast to restrike said lamp when said quantum of timing information indicates that said cool-down period of said lamp has elapsed.

4. The apparatus of claim 2 , wherein said control circuit is configured to:

permit said ballast to restrike said lamp when said quantum of timing information indicates that a predetermined period has elapsed;

detect if said lamp is receiving power from said power supply; and

reinitialize said timer circuit and increment said predetermined period if said lamp is not ignited by a restrike.

5. The apparatus of claim 1 , wherein:

said resistive-capacitive circuit is configured to have a variable RC time constant; and said variable RC time constant is set to a low value while said resistive-capacitive circuit is being charged and a high value during said timing phase.

6. An apparatus for a fast reignition of a high intensity discharge lamp comprising:

a ballast operatively coupled to said lamp, and configured to receive power from a power supply; and

a resistive-capacitive timer circuit configured to be charged by said power supply, discharge when said lamp ceases to receive power from said power supply, and output a timer voltage;

wherein said ballast will not strike said lamp if said timer voltage is above a predetermined voltage level;

wherein said timer circuit further comprises a resistive-capacitive circuit configured to be charged by said power supply when said lamp is receiving power from said power supply, to discharge when said timer circuit is in said timing phase, and to output a timer voltage; and

wherein said control circuit is configured to permit said ballast to restrike said lamp when said timer voltage drops below a predetermined level which indicates that a cool-down period of said lamp has elapsed.

7. The apparatus of claim 6 , further comprising:

a control circuit configured to store said predetermined voltage level in a non-volatile memory, and to compare said timer voltage to said predetermined voltage level;

wherein said timer voltage is substantially equivalent to said predetermined voltage level when said lamp has ceased to receive power from said power supply for a period of time equal to said cool-down period of said lamp.

8. The apparatus of claim 7 , wherein said resistive-capacitive timer circuit is configured to have a low RC time constant while being charged and a high RC time constant while being discharged.

9. The apparatus of claim 8 , wherein said control circuit is configured to check said timer voltage during a startup phase, and wait to send a strike signal to said ballast if said timer voltage is not below a predetermined threshold.

10. A method for a fast reignition of a high intensity discharge lamp comprising the steps of:

shifting a timer circuit into a timing phase when said lamp has ceased to receive power from a power supply;

producing a quantum of timing information using an internally powered timer system during said timing phase; and

limiting a ballast from re-striking said lamp for a time period based at least in part on said quantum of timing information;

wherein said timer circuit further comprises a resistive-capacitive circuit configured to be charged by said power supply when said lamp is receiving power from said power supply, to discharge when said timer circuit is in said timing phase, and to output a timer voltage; and

wherein a control circuit is configured to permit said ballast to restrike said lamp when said timer voltage drops below a predetermined level which indicates that a cool-down period of said lamp has elapsed.

11. The method from claim 10 , further comprising the steps of:

initializing said timer circuit when said lamp is ignited;

wherein said timer circuit is a clock circuit configured to be powered by a battery and run when said lamp ceases to receive power from said power supply.

12. The method of claim 11 , wherein said time period is set by said cool-downperiod of said lamp.

13. The method of claim 11 , further comprising the steps of:

detecting if said lamp is ignited;

incrementing a predetermined period of time if said lamp is not ignited; and

reinitializing said timer circuit if said lamp is not ignited;

wherein said time period is set by said predetermined period of time.

14. The method from claim 10 , further comprising the steps of:

charging said resistive-capacitive circuit with said power supply when said lamp is receiving power from said power supply; and

discharging said resistive-capacitive circuit when said timer circuit is in said timing phase;

wherein said timer circuit comprises said resistive-capacitive circuit.

15. The method from claim 14 , wherein said time period is set by a predetermined voltage level past which said timer voltage drops when said cool-down period of said lamp has elapsed.

16. The method from claim 14 , further comprising the steps of:

lowering a variable RC time constant of said resistive-capacitive circuit when said resistive-capacitive circuit is being charged; and

increasing said variable RC time constant of said resistive-capacitive circuit when said timer circuit is in said timing phase.

17. The method of claim 14 , further comprising the steps of:

detecting if said lamp is ignited;

incrementing said variable RC time constant of said resistive-capacitive circuit if said lamp is not ignited; and

reinitializing said timer circuit if said lamp is not ignited.