| 摘要 |
PROBLEM TO BE SOLVED: To provide a cold-cathode tube lighting device which has a stable luminance when the cold-cathode tube is put on at both ends of the input points. SOLUTION: This cold-cathode tube lighting device has a tube current detector circuit 50 detecting a first current each which flows through secondary sides of transformers 44, 45 from lower-voltage sides of secondary sides 44b and 45b and also each of second currents which flow through resonant capacitors 46 and 47. A difference of the first and the second currents is found at each of separately excited inverters and based on the difference a tube current of the cold cathode tube 48 is found, and further, a frequency of drive pulse voltage e1 and e2 is changed by a voltage control oscillator 41 so that this tube current may become a predetermined value, and as a result, the luminance of this cold-cathode tube is maintained at a stable level. COPYRIGHT: (C)2006,JPO&NCIPI |
