| 摘要 |
PROBLEM TO BE SOLVED: To satisfy both the suppression of a temperature at high temperatures and an improvement in the deterioration of a service life of a fluorescent lamp at low temperatures by reducing a tube current at high temperatures and making a constant tube current flow at room temperature or lower in an inverter to regulate the tube current in accordance with surrounding temperatures. SOLUTION: A midpoint of a thermistor 7 and a voltage dividing resister 8 connected between constant voltages is connected via a diode 9 to a voltage inverted from a tube current flowing in a fluorescent lamp 2 by a resister for detecting a current 3, and rectified and smoothed by a diode 4 and a smoothing capacitor 5. The midpoint voltage of the thermistor 7 and the dividing resister 8 makes the tube current constant by setting the midpoint voltage lower than the voltage obtained by smoothing the tube current at room temperature. The midpoint voltage only at high temperatures becomes higher than the voltage obtained by smoothing the tube current, then, makes the tube current low roughly in inverse proportion to temperatures. COPYRIGHT: (C)2005,JPO&NCIPI |
