Title:
DISCHARGE LAMP LIGHTING CIRCUIT
Document Type and Number:
Japanese Patent JP3279202
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To secure the stability at the time of igniting a discharge lamp by controlling duty ratio of the driving pulse to be applied to a switching element so as to maintain a large load current flowing to a discharge lamp immediately after igniting the lamp.
SOLUTION: Comparison voltage of a voltage detection setting circuit 3 is set at 180V, and in the case where Vdc is lower than 180V, lighting condition is judged, and in the case where Vdc is higher than 180V, extinguishing condition is judged. Consequently, before lighting a discharge lamp 6, load current is increased with passing of time immediately after lighting the lamp, and the voltage detection setting circuit 3 is operated till the output voltage of a load voltage detecting circuit 4 becomes lower than 180V so as to increase the load current. When a load current value, which can obtain the output voltage at 180V of the load voltage detecting circuit 4, is detected, operation of the voltage detection setting circuit 3 is stopped. A transistor Q of a comparison circuit 7 is electrified when the comparison voltage El becomes 16V.
Inventors:
Chikara Amano
Application Number:
JP30730896A
Publication Date:
April 30, 2002
Filing Date:
October 31, 1996
Export Citation:
Assignee:
Onkyo Corporation
International Classes:
H05B41/282; (IPC1-7): H05B41/282
Domestic Patent References:
| JP878176A | ||||
| JP682799U |
Attorney, Agent or Firm:
Yataro Sato
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