Liquid crystal backlight driving system

The utility model provides a liquid crystal backlight driving system, comprising a constant current driving integrated circuit, a liquid crystal backlight source, an analog-to-digital converter, a comparator, a microcontroller and an and gate circuit, and also a temperature sensor located in the interior of the liquid crystal backlight source and used for detecting the working environment temperature of the liquid crystal backlight source; wherein, the analog-to-digital converter is responsible for transforming an electrical signal transferred by the temperature sensor and representing the environment temperature into a digital signal, and outputting to the comparator; the comparator is responsible for comparing the digital signal with a temperature threshold value, and outputting the comparison result to the microcontroller; the microcontroller is responsible for generating pulse-width modulation signals of different duty ratios according to the comparison result and outputting to the and gate circuit; and the and gate circuit is responsible for carrying out and operations of the pulse-width modulation signals and switch enabling signals inputted externally, and outputting to a switch enabling signal end of the constant current driving integrated circuit to control the output of the constant current driving integrated circuit.