| 主权项 |
1. A light emitting diode string driving circuit, comprising:
a plurality of light emitting diode (LED) strings; a power supply unit electrically coupled to the LED strings and configured to receive an input voltage and accordingly output a driving voltage to the LED strings; a comparison unit configured to receive the input voltage and output a first control signal according to a relationship between the input voltage and a predetermined voltage; a control unit electrically coupled to the comparison unit and configured to receive the first control signal and generate a second control signal according to a potential level of the first control signal; and a switch unit electrically coupled to the control unit, the power supply unit and the LED strings, the switch unit comprising a plurality of switch elements, the switch elements each being controlled by the second control signal and thereby forming various electrical loops, wherein when the switch unit has one specific electrical loop and thereby configuring the LED strings corporately to form a parallel loop, the LED strings in the parallel loop are driven and controlled by the driving voltage; wherein when the switch unit has another specific electrical loop and thereby configuring the LED strings corporately to form a series loop, the LED strings in the series loop are driven and controlled by the driving voltage. |
