| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp driving circuit capable of having designated light-emitting intensity in spite of variation of circumferential temperature in a simple structure where a part of existing circuit elements are replaced. SOLUTION: The cold-cathode fluorescent lamp driving circuit comprises a transformer 50 for driving a CCFL 300 and its drive circuit 200, a PWM control section 400 for controlling the same transformer 50 and its drive circuit 200, and an input current detection section 100 for detecting voltage corresponding to an effective value of input current IL2 as a vector sum of tube current IL1 and leaked current. The input current detection section 100 has a detection resistor 10, rectifying diodes 11, 12, a smoothing capacitor 13, and partial pressure resistors 14, 15. A resistance value of at least one of the resistors 14, 15 is changed in response to temperature change, and temperature-compensated voltage is given to the PWM control section 400. Thus, the CCFL 300 is set up to be the designated light-emitting intensity in spite of variation of the peripheral temperature on the basis of replacement of resistance elements. COPYRIGHT: (C)2009,JPO&INPIT |
