Patent ID: 8638049
Filing Date: 2014-01-28
Classification: H05B

Abstract:
1. A light emitting diode (LED) driving device, comprising: a driving unit, for producing a driving signal to drive a LED; and a plurality of selection units, coupled to the driving unit, and respectively corresponding to different current values, wherein the driving unit selects one of the selection units according a duty cycle of a first pulse width modulation (PWM) signal, and takes a current value corresponding to the selected selection unit as a current value of the driving signal, and the driving unit generates a second PWM signal according to the duty cycle of the first PWM signal, and takes a duty cycle of the second PWM signal as a duty cycle of the driving signal, wherein the duty cycle of the second PWM signal is greater than or equal to the duty cycle of the first PWM signal, wherein a ratio of the duty cycle of the second PWM signal and the duty cycle of the first PWM signal is inversely proportional to the radio of the current value of the driving signal and a predetermined current value.