Claims
- 1. A lighting circuit to operate a discharge lamp with a bi-pin base, the lighting circuit comprising a bypass circuit coupled across pins provided to a filament in the discharge lamp, wherein the bypass circuit is relatively inactive when the filament is in working condition and becomes active to allow continued starting and lighting of the discharge lamp when the filament is broken.
- 2. The lighting circuit of claim 1, wherein the bypass circuit is a pair of diodes coupled in parallel and opposite directions.
- 3. The lighting circuit of claim 1, further comprising a dimming circuit configured to vary the amplitude of an input voltage in response to a control signal to adjust the brightness of the discharge lamp.
- 4. The lighting circuit of claim 1, further comprising:
a rectifier circuit configured to convert a substantially alternating current input voltage at a first frequency to a rectified voltage; and an oscillator circuit configured to receive the rectified voltage and to produce a substantially alternating current output voltage at a second frequency to drive the discharge lamp, wherein the second frequency is relatively higher than the first frequency.
- 5. A method for extending the life of a discharge lamp, the method comprising coupling a redundant circuit across terminals provided to a cathode in the discharge lamp, wherein the redundant circuit is normally dormant but provides a conductive path between the terminals after the cathode wears out.
- 6. The method of claim 5, wherein the redundant circuit is a diode.
- 7. A lamp driver comprising means for operating a discharge lamp without retrofit when one or more filaments are burnt out.
RELATED APPLICATION
[0001] The present application is a divisional of U.S. application Ser. No. 10/205,290, filed Jul. 23, 2002, now allowed, which claims priority benefit under 35 U.S.C. § 119(e) of Provisional Application No. 60/339,717, filed Nov. 2, 2001.
Provisional Applications (1)
|
Number |
Date |
Country |
|
60339717 |
Nov 2001 |
US |
Divisions (1)
|
Number |
Date |
Country |
Parent |
10205290 |
Jul 2002 |
US |
Child |
10815919 |
Apr 2004 |
US |