Patent ID: 8884545

Claim:
A light emitting diode (LED) driving system, for driving a plurality of LED strings, comprising: a plurality of current sources, respectively connected to the LED strings; a multi-phase control signal generator, for generating a plurality of multi-phase control signals that respectively control turn-on or turn-off of the current sources so as to selectively conduct current through the LED strings; and a voltage selecting circuit, for receiving a plurality of voltages between the LED strings and the current sources, and selecting one of the voltages as a selected voltage to output a corresponding feedback voltage, comprising; a plurality of transistor switch pairs connected in parallel; wherein each transistor switch pair comprises: a first transistor for receiving one the voltages, es, and the feedback voltage is substantially equal to a sum of the selected voltage and a threshold conduct voltage of the first transistor; and a second transistor connected in serial to the first transistor, wherein each second transistor is selectively conducted by receiving one of the multi-phase control signals.