Patent ID: 7675246

Claim:
A driving circuit for providing feedback control and open-circuit protection, the driving circuit comprising: at least one light-emitting device; a voltage regulator circuit, coupled to the light-emitting device, for providing a driving voltage to drive the light-emitting device; a first resistor, coupled to the output end of the voltage regulator circuit; a second resistor, coupled to the first resistor in series, wherein the first resistor and the second resistor are used for dividing the driving voltage to generate a divided driving voltage; an analysis and decision circuit, coupled to the light-emitting device, for determining whether the light-emitting device is open-circuit to generate a decision result, wherein the analysis and decision circuit comprises: a second comparator, having a first input end coupled to a joint point of the first resistor and the second resistor for receiving the divided driving voltage and a second input end for receiving a second reference voltage, the second comparator used for comparing the divided driving voltage with the second reference voltage to generate a second comparison signal; at least one open-circuit detector, having an input end coupled to the light-emitting device and an output end for outputting a detection signal, the open-circuit detector used for detecting a status of the light-emitting device; and a control logic, coupled to the output end of the second comparator and the output end of the open-circuit detector, the control logic used for generating the decision result according to the second comparison signal and the detection signal; and a selecting circuit, coupled between the analysis and decision circuit and the voltage regulator circuit, for selecting a maximum forward bias voltage corresponding to the light-emitting device to generate a feedback signal according to the decision result and for transmitting the feedback signal to the voltage regulator circuit, wherein the voltage regulator circuit adjusts the driving voltage according to the feedback signal.