Patent ID: 8248439

Claim:
A backlight controller for driving a plurality of light emitting diode (LED) strings, said backlight controller comprising: feedback circuitry generating a plurality of feedback signals indicative of a plurality of currents flowing through said plurality of LED strings respectively; encoder circuitry coupled to said feedback circuitry, said encoder circuitry generating a code signal indicative of a total number of operative LED strings among said plurality of LED strings based on said feedback signals; and phase array circuitry coupled to said encoder circuitry, said phase array circuitry generating a plurality of saw tooth signals according to said code signal, wherein a phase shift amount between two adjacent signals of said plurality of saw tooth signals is determined by the total number of said operative LED strings, and wherein said phase array circuitry compares each of said saw tooth signals with a dimming control signal to generate a plurality of phase shift signals so as to respectively control said operative LED strings, wherein said phase array circuitry further comprises: a frequency divider dividing an oscillation signal according to said code signal to generate a plurality of phase shift pulse signals; and control circuits coupled to said frequency divider, said control circuits converting said plurality of phase shift pulse signals to said plurality of saw tooth signals, respectively.