Backlight control circuit having a duty ratio determining unit and method for controlling lighting of a lamp using same

摘要

An exemplary backlight control circuit includes a lamp, a transformer, and a lamp driving circuit. The lamp driving circuit includes a duty ratio determining unit, a duty ratio adjusting unit, and an output unit. The output unit is configured for outputting two pulse signals having a same duty ratio and opposite phases to the transformer. The transformer is configured for generating an alternating voltage for driving the lamp. The duty ratio determining unit is configured for determining if the duty ratio of the pulse signals is in a predetermined duty ratio range. The duty ratio adjusting unit is configured for adjusting the duty ratio of the pulse signals in order to adjust a brightness of the lamp.