Patent ID: 9030126
Filing Date: 2015-05-12
Classification: H05B

Abstract:
1. An LED driving device, comprising: a first constant current source circuit, outputting a first constant current to a first node such that the first constant current flows into a first LED module disposed between a driving node and the first node, wherein the first constant current source circuit has a first detection node for generating a first detection signal in response to a voltage level of the first node; and a voltage control circuit, coupled to the first detection node for outputting a control signal in response to the first detection signal to a regulator circuit for controlling and adjusting the regulator circuit to output a driving voltage to the driving node; and a second constant current source circuit, outputting a second constant current to a second node such that the second constant current flows into a second LED module disposed between the driving node and the second node, wherein the second constant current source circuit has a second detection node for generating a second detection signal in response to a voltage level of the second node; wherein the voltage control circuit is coupled to the second detection node for generating the control signal according to the first detection signal and the second detection signal to control the regulator circuit to adjust the driving voltage; wherein the voltage control circuit comprises a detecting and comparing circuit for receiving and comparing the first detection signal and the second detection signal; wherein when the voltage level of the first detection signal and the voltage level of the first node are in positive correlation with each other, the detecting and comparing circuit outputs a voltage difference between a working voltage and a lower one selected from the first detection signal and the second detection signal as a control signal for controlling the regulator circuit to increase the driving voltage; and wherein when the voltage level of the first detection signal and the voltage level of the first node are in negative correlation with each other, the detecting and comparing circuit outputs the voltage difference between the working voltage and a higher one selected from the first detection signal and the second detection signal as the control signal for controlling the regulator circuit to increase the driving voltage.