Title:
DISCHARGE LAMP LIGHTING DEVICE
Document Type and Number:
Japanese Patent JP3050256
Kind Code:
B2
Abstract:
PURPOSE: To provide a discharge lamp lighting device in which no load is generated in a lighting circuit even at preheating of a discharge lamp or secondary short-circuit.
CONSTITUTION: At normal lighting, the voltage across a second capacitor C2 has almost the same waveform as the output of a rectifying circuit. The base voltage of a transistor Q3 is lowered, the base capacitance of a transistor Q1 is increased to generally oscillate an inverter circuit 3, and a fluorescent lamp FL is lighted as usual. At an abnormality such as long-time preheating state or secondary side short-circuit, the voltage of the second capacitor C2 becomes a voltage in which a high frequency is superposed on the voltage of the rectifying circuit 1. The base voltage of the transistor Q3 is raised, and the base capacitance of the transistor Q1 is lowered to lower the output of the inverter circuit 3. The stress added to a part such as the transistor Q1 is reduced, and the stress of a semiconductor part such as the transistor Q1 is protected.
Inventors:
Masahiro Sugiyama
Toshiyuki Hiraoka
Toshiyuki Hiraoka
Application Number:
JP29011392A
Publication Date:
June 12, 2000
Filing Date:
October 28, 1992
Export Citation:
Assignee:
Toshiba Lighting & Technology Corporation
International Classes:
H05B41/24; H05B41/282; (IPC1-7): H05B41/282; H05B41/24
Domestic Patent References:
| JP4137499A | ||||
| JP4217878A | ||||
| JP6141549A | ||||
| JP5336755A | ||||
| JP5284757A | ||||
| JP5211774A | ||||
| JP5161366A | ||||
| JP589987A | ||||
| JP564430A | ||||
| JP3285295A | ||||
| JP389494A | ||||
| JP365064A | ||||
| JP329298A | ||||
| JP2192695A | ||||
| JP1252175A | ||||
| JP60189899A | ||||
| JP59181967A |
Attorney, Agent or Firm:
Kabazawa Xiang (2 people outside)