Claims
- 1. A discharge lamp driving device comprising:
- first means for supplying a discharge lamp with power that is higher than normal during a start-up period and with power that thereafter gradually decreases to normal power during a stabilizing period; and
- second means for shortening said stabilizing period when a dummy resistor having a specific resistance is connected to said first means instead of said discharge lamp.
- 2. A discharge lamp driving device as in claim 1 wherein:
- said first means comprises a time constant circuit providing a time constant defining said stabilizing period; and
- said second means comprises a circuit for changing the time constant of said time constant circuit when said discharge lamp is replaced by said dummy resistor.
- 3. A discharge lamp driving device as in claim 2 wherein:
- said time constant circuit comprises a first series circuit of a capacitor and a first resistor;
- said circuit for shortening the stabilizing period comprises a second series circuit of a second resistor which has a resistance smaller than that of said first resistor and a switch member;
- said second series circuit is connected in parallel with said first resistor; and
- said switch member connects said second resistor when power is supplied to said dummy resistor.
- 4. A discharge lamp driving device as in claim 2 wherein:
- said second means further comprises a circuit for operating said circuit for changing the time constant when voltage applied to said dummy resistor is lower than a preset level.
- 5. A method of testing a discharge lamp driving circuit, said method comprising steps of:
- connecting a dummy resistor load to said discharge lamp driving circuit instead of a discharge lamp;
- initially supplying driving power to the connected load that is higher than normal discharge lamp operating power;
- detecting a voltage applied to said dummy resistor load; and
- reducing said driving power to normal power when said detected voltage indicates the presence of said dummy resistor as a connected load.
- 6. In a discharge lamp driver having an initial turn-on mode wherein power supplied to a connected discharge lamp is initially higher than normal lamp operating power during an initial stabilizing period, the improvement comprising:
- a load-type detector circuit connected to sense the presence of a substituted test load to a driver output instead of a discharge lamp; and
- a timing circuit connected to said detector shorter said initial stabilizing period when the presence of said substituted test load is detected.
- 7. A discharge lamp driver circuit comprising:
- a first timing circuit connected to cause a normal-mode gradual reduction in an initially higher than normal power output to a connected discharge lamp; and
- a second timing circuit connected to cause a more abrupt test-mode reduction to normal power output to a connected substitute test load thereby reducing the time required to test the operability of said driver circuit.
- 8. A method of testing a discharge lamp driver circuit, said method comprising:
- connecting a substitute test load instead of a discharge lamp to an output of the driver circuit; and
- reducing a normal start-up and stabilizing time used with a normal discharge lamp load thereby reducing the time required to test the operability of said driver circuit.
Priority Claims (1)
Number |
Date |
Country |
Kind |
8-271013 |
Oct 1996 |
JPX |
|
CROSS REFERENCE TO RELATED APPLICATION
The present application is based on and claims priority from Japanese Patent Application No. Hei 8-271013, filed on Oct. 14, 1996, the contents of which are incorporated herein by reference.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
5241242 |
Daub |
Aug 1993 |
|
5317237 |
Allison et al. |
May 1994 |
|
Foreign Referenced Citations (2)
Number |
Date |
Country |
A-2-51895 |
Feb 1990 |
JPX |
A-5-251189 |
Sep 1993 |
JPX |