| 摘要 |
A circuit for controlling the brightness of an LCD backlight is provided to generate chopping waves, synchronized with the PWM frequency inputted from the outside, in an inverter and control the on/off cycle of an inverter output current correspondingly to a DC voltage inputted from the outside. A circuit for controlling the brightness of an LCD backlight comprises the followings: a voltage level changing unit(110) for converting a direct current voltage signal inputted from the outside into a voltage level for input; a chopping wave generating unit(120) for producing a chopping wave voltage according to the on/off signal of a predetermined duty radio inputted from the outside; a chopping wave correcting unit(130) for compensating chopping waves generated from the chopping wave generating unit; and an inverter control unit(140) which compares the direct current voltage inputted from the voltage level changing unit with the chopping waves generated from the chopping wave generating unit to determine the duty ration of an output current, and controls the output current of the inverter. |
