Patent ID: 8773033

Claim:
A driving method for backlight unit of liquid crystal display, comprising: comparing a strength of a soft start signal with a predetermined signal through a comparator circuit, and generating a first comparison signal or a second comparison signal according to a comparison result; outputting a first frequency from a frequency modulation circuit according to the first comparison signal; increasing a rising rate of an output voltage of a boost converter according to the first frequency; generating the first comparison signal through the comparator circuit when the soft start voltage signal is smaller than the predetermined voltage signal; generating the second comparison signal when the soft start voltage signal is larger than the predetermined voltage signal; outputting a second frequency from the frequency modulation circuit according to the second comparison signal; and decreasing the rising rate of the output voltage of the boost converter according to the second frequency, wherein the first frequency is higher than the second frequency, and the rising rate of the output voltage of the boost converter controlled by the first frequency is faster than the rising rate of the output voltage of the boost converter controlled by the second frequency.