Electronic ballast for a high-pressure discharge lamp

• US 6,914,395 B2
• Filed: 11/26/2002
• Issued: 07/05/2005
• Est. Priority Date: 11/27/2001
• Status: Expired due to Term

• Current Assignee: Panasonic Electric Works Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Asahi Matsushita Electric Works Ltd. (Panasonic Holdings Corporation)
• Inventors: Shiomi, Tsutomu, Nakamura, Toshiaki, Kamoi, Takeshi, Maehara, Minoru, Iwahori, Yutaka, Yamauchi, Tokushi
• Primary Examiner(s): Tran, Thuy V.
• Application Number:
  US10/473,361
• Publication Number:
  US 20040113567A1
• Time in Patent Office: 952 Days
• Field of Search: 315/129, 315224-225, 315246-247, 315/291, 315/299, 315307-308, 315/360, 315/DIG.7, 315/226, 315/309
• US Class Current: 315/308
• CPC Class Codes: H05B 41/2882 the control resulting from an action on the static converter
• CPC Class Codes: H05B 41/2887 characterised by a controllable bridge in the final stage
• CPC Class Codes: H05B 41/36 Controlling
• CPC Class Codes: H05B 41/38 Controlling the intensity of light
• CPC Class Codes: H05B 41/388 for a transition from glow to arc
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

An electronic ballast for a high intensity discharge lamp (HID) includes a power converters, a controller, and a lamp power switch. In the power converter, an input DC voltage is converted into a ballast output power for lighting the HID lamp. The controller has a function to control the power converter and change the ballast output power. The lamp power switch detects a lamp output parameter indicated after the HID lamp starts discharge, identifies a lamp power of the HID lamp according to the lamp output parameter, and gives an identification signal indicating the lamp power. In response to this identification signal, the power converter outputs the ballast output power which matches with the lamp power identified.

Claims

1. An electronic ballast for a high intensity discharge (HID) lamp, said ballast comprising:

a power converter configured to convert an input DC voltage into a ballast output power for driving said HID lamp;

a controller configured to control said power converter to vary said ballast output power being supplied to said HID lamp; and

a lamp vower switch configured to monitor a lamp output parameter that said HID lamp exhibits after it starts discharging, discriminate a rated lamp power of said HID lamp based upon said monitored lamp output parameter, and provide a lamp power signal indicative of the discriminated rated lamp power.

said lamp power switch comprising;

a monitor configured to keep monitoring said lamp output parameter before said HID lamp comes into a stable lamp operating condition;

a timer configured to start counting a time when said HID lamp starts discharging, and output an enabling signal when said counted time exceeds a predetermined time; and

a lamp discriminator configured to compare said lamp output parameter with a predetermined reference value upon receiving said enabling signal, and provide said lamp power signal when said lamp output parameter satisfies a predetermined criteria; and

said controller being configured to vary said ballast output power to match with said rated lamp power of said HID lamp according to said lamp power signal received.

2. The ballast as set forth in claim 1, wherein said lamp output parameter is a transient lamp characteristic selected from a group consisting of a lamp voltage, a lamp current, and an optical characteristic that the HID lamp exhibits after it starts discharging and before it comes into the stable lamp operating condition.

3. The ballast as set forth in claim 2, wherein said lamp output parameter is a lamp voltage.

4. The ballast as set forth in claim 1, wherein said lamp power switch further comprises a rest counter configured to record a lamp rest time from a turn-off of said ballast to a restarting of said ballast, and provide to said comparator a rest signal which varies said reference value in accordance with said lamp rest time.

5. The ballast as set forth in claim 1, wherein

said lamp power switch further comprises a lamp aging monitor configured to monitor said lamp output parameter to determine a degree of a lamp aging, and

said lamp aging monitor configured to provide an aging signal indicative of said degree which varies said reference value for compensation of said lamp aging in discriminating said rated lamp power.

6. The ballast as set forth in claim 1, wherein said lamp output parameter is a lamp characteristic selected from a group consisting of a lamp voltage, a lamp current, and an optical characteristic that the HID lamp exhibits after it comes into the stable operating condition.

7. The ballast as set forth in claim 6, wherein said lamp output parameter is a lamp voltage.

8. The ballast as set forth in claim 1, wherein said timer configured to provide another enabling signal after a predetermined interval from the time of providing said enabling signal so that said lamp discriminator responds to provide another lamp power signal indicative of the rated lamp power located at the timing of providing said another enabling signal, whereby said controller configured to vary said ballast output power in match with the rated lamp power located last.

9. An electronic ballast for a high intensity discharge (HID) lamp, said ballast comprising:

a power converter configured to convert an input DC voltage into a ballast output power for driving said HID lamp;

a controller configured to control said power converter to vary said ballast output power being supplied to said HID lamp; and

a lamp power switch configured to monitor a lamp output parameter that said HID lamp exhibits after it starts discharging, discriminate a rated lamp power of said HID lamp based upon said monitored lamp output parameter, and provide a lamp power signal indicative of the discriminated rated lamp power,

said lamp power switch comprising;

a monitor configured to monitor said lamp output parameter before said HID lamp comes into a stable lamp operating condition, and provide a detection signal when said lamp output parameter exceeds a critical level;

a timer configured to start counting a time upon beginning of the discharging by said HID lamp and stop counting the time upon receiving of said detection signal, thereby giving an accumulated time period from the beginning of the discharging to the receiving of said detection signal; and

a lamp discriminator configured to compare said accumulated time period with a predetermined reference time and provide said lamp power signal when said accumulated time period satisfies a predetermined criteria, and said controller configured to vary said ballast output power to match with said rated lamp power of said HID lamp according to said lamp power signal received.

10. The ballast as set forth in claim 9, wherein said lamp output parameter is a transient lamp characteristic selected from a group consisting of a lamp voltage, a lamp current, and an optical characteristic that the HID lamp exhibits after it starts discharging and before it comes into the stable lamp operating condition.

11. The ballast as set forth in claim 10, wherein said lamp output parameter is a lamp voltage.

12. The ballast as set forth in claim 9, wherein said lamp power switch further comprises a rest counter configured to record a lamp rest time from a turn-off of said ballast to a restarting of said ballast, and provide to said comparator a rest signal which varies said reference time in accordance with said lamp rest time.

13. The ballast as set forth in claim 9, wherein

said lamp power switch further comprises a lamp aging monitor configured to monitor said lamp output parameter to determine a degree of a lamp aging, and

said lamp aging monitor configured to provide an aging signal indicative of said degree which varies said reference time for compensation of said lamp aging in discriminating said rated lamp power.

14. The ballast as set forth in claim 9, wherein said timer configured to provide another enabling signal after a predetermined interval from the time of providing said enabling signal so that said lamp discriminator responds to provide another lamp power signal indicative of the rated lamp power located at the timing of providing said another enabling signal, whereby said controller configured to vary said ballast output power in match with the rated lamp power located last.

15. An electronic ballast for a high intensity discharge (HID) lamp, said ballast comprising:

a power converter configured to convert an input DC voltage into a ballast output power for driving said HID lamp;

a controller configured to control said power converter to vary said ballast output power being supplied to said HID lamp; and

a lamp power switch configured to monitor a lamp output parameter that said HID lamp exhibits after it starts discharging, discriminate a rated lamp power of said HID lamp based upon said monitored lamp output parameter, and provide a lamp power signal indicative of the discriminated rated lamp power,

said lamp power switch comprising;

a monitor configured to keep monitoring said lamp output parameter after said HID lamp comes into a stable lamp operating condition;

a timer configured to start counting a time when said HID lamp starts discharging and provide an enabling signal when said counted time exceeds a predetermined time indicative of that said HID lamp comes into the stable lamp operating condition;

a memory configured to store the lamp output parameter that the HID lamp exhibits after reaching the stable lamp operating condition, said lamp output parameter being predetermined for each of different combinations of said ballast output power and said rated lamp power; and

a lamp discriminator configured to reference said memory upon receiving said enabling signal to locate one of said rated lamp power in match with the lamp output parameter being monitored, and provide said lamp power signal indicative of the located rated lamp power, and

said controller configured to receive said lamb power signal and vary said ballast output power in match with the located rated lamp power.

16. The ballast as set forth in claim 15, wherein said timer configured to provide another enabling signal after a predetermined interval from the time of providing said enabling signal so that said lamp discriminator responds to provide another lamp power signal indicative of the rated lamp power located at the timing of providing said another enabling signal, whereby said controller configured to vary said ballast output power in match with the rated lamp power located last.

17. An electronic ballast for a high intensity discharge (HID) lamp, said ballast comprising:

a power converter configured to convert an input DC voltage into a ballast output power for driving said HID lamp;

a controller configured to control said power converter to vary said ballast output power being supplied to said HID lamp; and

a lamp power switch configured to monitor a lamp output parameter that said HID lamp, exhibits after it starts discharging, discriminate a rated lamp power of said HID lamp based upon said monitored lamp output parameter, and provide a lamp power signal indicative of the discriminated rated lamp power,

said lamp power switch comprising;

a frequency monitor configured to keep monitoring a frequency about which said HID lamp gives an acoustic resonance after said HID lamp comes into a stable lamp operating condition;

a memory configured to store said frequency that the HID lamp exhibits after reaching the stable lamp operating condition, said frequency being predetermined for each of different combinations of said ballast output power and said rated lamp power; and

a lamp discriminator configured to reference said memory to locate one of said rated lamp power in match with said frequency being monitored, and provide said lamp power signal indicative of the located rated lamp power, and

said controller configured to receive said lamp power signal and vary said ballast output power in match with the located rated lamp power.

18. An electronic ballast for a high intensity discharge (HID) lamp, said ballast comprising:

a power converter configured to convert an input DC voltage into a ballast output power for driving said HID lamp;

a controller configured to control said power converter to vary said ballast output power being supplied to said HID lamp; and

a lamp power switch configured to monitor a lamp output parameter that said HID lamp exhibits after it starts discharging, discriminate a rated lamp power of said HID lamp based upon said monitored lamp output parameter, and provide a lamp power signal indicative of the discriminated rated lamp power,

said lamp power switch comprising;

a memory configured to store a plurality of different said ballast output powers; and

a selector configured to select one of said ballast output power as a default one to be initially supplied to said HID lamp,

said selector having an input terminal configured to receive an external signal by which said selector is activated to select any one of said ballast output power as said default one, and

said controller configured to receive said lamp power signal and vary said ballast output power in match with said rated lamp power.

19. The ballast as set forth in claim 18, wherein said lamp power switch is configured to store in said memory the rated lamp power as an updated lamp power each time it is discriminated, and

said selector configured to assign said updated lamp power as said default one each time said ballast is activated.

20. An electronic ballast for a high intensity discharge (HID) lamp, said ballast comprising:

a power converter configured to convert an input DC voltage into a ballast output power for driving said HID lamp;

a controller configured to control said power converter to vary said ballast output power being supplied to said HID lamp; and

a lamp power switch configured to monitor a lamp output parameter that said HID lamp exhibits after it starts discharging, discriminate a rated lamp power of said HID lamp based upon said monitored lamp output parameter, and provide a lamp power signal indicative of the discriminated rated lamp power,

said lamp power switch comprising a lamp life monitor configured to monitor said lamp output parameter to provide a life-end signal when said HID lamp is determined by said lamp output parameter to come into near end-of-life condition, and

said controller configured to vary said ballast output power in match with said rated lamp power according to said lamp power signal received, and respond to said life-end signal for reducing said ballast output power to a minimum.

21. An electronic ballast for a high intensity discharge (HID) lamp, said ballast comprising:

a power converter configured to convert an input DC voltage into a ballast output power for driving said HID lamp;

a controller configured to control said power converter to vary said ballast output power being supplied to said HID lamp; and

a lamp power switch configured to monitor a lamp output parameter that said HID lamp exhibits after it starts discharging, discriminate a rated lamp power of said HID lamp based upon said monitored lamp output parameter, and provide a lamp power signal indicative of the discriminated rated lamp power.

said lamp power switch comprising;

a color temperature monitor configured to monitor a color temperature that said HID lamp exhibits after it comes into a stable lamp operating condition;

a memory configured to store said color temperature that the HID lamp exhibits after reaching the stable lamp operating condition, said color temperature being predetermined for each of different combinations of said ballast output power and said rated lamp power; and

a lamp discriminator configured to reference said memory to locate one of said rated lamp power in match with said color temperature being monitored, and provide said lamp power signal indicative of the located rated lamp power, and

said controller configured to receive said lamp power signal and vary said ballast output power in match with the located rated lamp power.

22. An electronic ballast for a high intensity discharge (HID) lamp, said ballast comprising:

a power converter configured to convert an input DC voltage into a ballast output power for driving said HID lamp;

a controller configured to control said power converter to vary said ballast output power being supplied to said HID lamp; and

a lamp power switch configured to monitor a lamp output parameter that said HID lamp exhibits after it starts discharging, discriminate a rated lamp power of said HID lamp based upon said monitored lamp output parameter, and provide a lamp power signal indicative of the discriminated rated lamp power.

said lamp power switch comprising;

a color deviation monitor configured to monitor a color difference that said HID lamp exhibits after it comes into a stable lamp operating condition;

a memory configured to store said color deviation that the HID lamp exhibits after reaching the stable lamp operating condition, said color deviation being predetermined for each of different combinations of said ballast output power and said rated lamp power; and

a lamp discriminator configured to reference said memory to locate one of said rated lamp power in match with said color deviation being monitored, and provide said lamp power signal indicative of the located rated lamp power, and

said controller configured to receive said lamp power signal and vary said ballast output power in match with the located rated lamp power.

23. An electronic ballast for a high intensity discharge (HID) lamp, said ballast comprising:

a power converter configured to convert an input DC voltage into a ballast output power for driving said HID lamp;

a controller configured to control said power converter to vary said ballast output power being supplied to said HID lamp; and

a lamp power switch configured to monitor a lamp output parameter that said HID lamp exhibits after it starts discharging, discriminate a rated lamp power of said HID lamp based upon said monitored lamp output parameter, and provide a lamp power signal indicative of the discriminated rated lamp power,

said controller configured to receive said lamp power signal and vary said ballast output power in match with said rated lamp power,

said lamp power switch comprising;

a monitor configured to monitor said lamp output parameter; and

a memory configured to store the lamp output parameter which is exhibited by said HID lamp and is predetermined for each of different combinations of said ballast output power and said rated lamp power; and

a lamp discriminator configured to reference said memory to locate one of said rated lamp power in match with the lamp output parameter being monitored, and provide said lamp power signal indicative of the located rated lamp power,

said controllers in response to said lamp power signal, configured to vary said ballast output power in match with the located rated lamp power,

said memory further configured to store a plurality of ballast output powers as default established ballast output powers,

said lamp power switch further comprising a verifier which issues a stop signal when said located rated lamp power is not coincident with any one of said default established ballast output powers, and

said controller, in response to said stop signal, configured to cease providing said ballast output power.

24. An electronic ballast for a high intensity discharge (HID) lamp, said ballast comprising:

a power converter configured to convert an input DC voltage into a ballast output power for driving said HID lamp;

a controller configured to control said power converter to vary said ballast output power being supplied to said HID lamp; and

a lamp power switch configured to monitor a lamp output parameter that said HID lamp exhibits after it starts discharging, discriminate a rated lamp power of said HID lamp based upon said monitored lamp output parameter, and provide a stop signal when said rated lamp power thus discriminated is not coincident with a default value of said ballast output power set to said ballast,

said controller configured to receive said stop signal to cause said power converter to stop providing said ballast output power.