Patent ID: 8711119

Claim:
a display system comprising: a touch screen comprising a plurality of touch sensors and a light source that backlights a display panel; and a driving circuit coupled to said touch screen, said driving circuit comprising: a converter that receives an input voltage generated by a power source, and that provides a first output voltage to said light source according to a driving signal; and a controller, coupled to said converter, that converts said first output voltage to a second output voltage to drive said touch sensors, that generates a voltage feedback signal indicating whether said second output voltage reaches a desired voltage level, and that generates a current feedback signal indicating whether a current flowing through said light source reaches a desired current level, wherein said controller compares said voltage feedback signal with said current feedback signal and selects a feedback signal from said voltage feedback signal and said current feedback signal according to a result of said comparison, wherein said controller generates said driving signal to adjust said first output voltage according to said selected feedback signal, such that said current and said second output voltage are adjusted to said desired current level and said desired voltage level, respectively.