Title:
COLD CATHODE TUBE LIGHTING DEVICE
Document Type and Number:
Japanese Patent JP3256992
Kind Code:
B2
Abstract:
PURPOSE: To provide a cold cathode tube lighting device which does not require components for a ballast on the secondary side and which can hold the current of a cold cathode tube constant even if the voltage of the cold cathode tube is changed and which can restrain lowering of the brightness of the cold cathode tube at low temperatures while simply setting the current of the cold cathode tube and which can use an inverter transformer of low output voltage.
CONSTITUTION: A cold cathode tube 8 is directly connected to the secondary side of a voltage resonance type Royer circuit to which power is fed from a low voltage constant current source 9. The output voltage of the voltage resonance type Royer circuit is proportional to input voltage and the input voltage is equal to the output voltage. Power consumed at the cold cathode tube is expressed as the product of tube voltage and tube current. Power output from the constant current source 9 is the product of the voltage and the current. Therefore, the tube current is proportional to the input current of the Royer circuit.
Inventors:
Makoto Imaguchi
Application Number:
JP25087591A
Publication Date:
February 18, 2002
Filing Date:
September 30, 1991
Export Citation:
Assignee:
Matsushita Electric Industrial Co., Ltd
International Classes:
G09F13/26; H02M7/48; H05B41/24; (IPC1-7): H05B41/24; G09F13/26; H02M7/48
Domestic Patent References:
| JP2227999A | ||||
| JP60100A |
Attorney, Agent or Firm:
Fumio Iwahashi (2 others)