Light emitting diode driving chip having eight or six pins, drving system using the light emitting diode driving chip, and related method thereof

A light emitting diode (LED) driving system, comprising:

• an LED driving chip, having eight pins, the LED driving chip comprising:
• a current regulating circuit, arranged to selectively output a first current, a second current, a third current and a fourth current to a first pin, a second pin, a third pin and a fourth pin of the LED driving chip, respectively;
• a current control circuit, coupled to the current regulating circuit and a fifth pin, the current control circuit arranged to receive an adjusting signal from the fifth pin to control the first current, the second current, the third current and the fourth current;
• a feedback voltage control circuit, arranged to output a feedback voltage to a sixth pin according to a first specific voltage and a setting voltage, wherein the first specific voltage is selected from the first, the second, the third and the fourth voltages respectively corresponding to the first, the second, the third and the fourth pins;
• a protection circuit, arranged to determine whether a voltage difference between a second specific voltage and the first specific voltage is larger than a threshold value, wherein the second specific voltage is selected from the first, the second, the third and the fourth voltages, and when the voltage difference is larger than the threshold value, the protection circuit controls the current regulating circuit to stop conducting current to a specific pin corresponding to the first specific voltage to make a voltage of the specific pin no longer the first specific voltage, and the feedback voltage control circuit stops utilizing the voltage of the specific pin to output the feedback voltage;
• and
• a power supply, having a feedback control end coupled to the sixth pin, the power supply arranged to generate a direct current (DC) power voltage at an output end according to the feedback voltage;
• at least one LED, coupled between the DC power voltage and at least one pin selected from the first pin, the second pin, the third pin and the fourth pin;
• and
• an adjusting circuit, coupled to the fifth pin, the adjusting circuit arranged to generate the adjusting signal according to a brightness control signal.

A light emitting diode (LED) driving chip having sixth pins, comprising:

• a current regulating circuit, arranged to selectively output a first current and a second current to a first pin and a second pin, respectively;
• a current control circuit, coupled to the current regulating circuit and a third pin, the current control circuit arranged to receive an adjusting signal from the third pin to control the first current and the second current;
• a feedback voltage control circuit, arranged to output a feedback voltage to a fourth pin according to a first specific voltage and a setting voltage, wherein the first specific voltage is selected from a first voltage and a second voltage respectively corresponding to the first pin and the second pin;
• and
• a protection circuit, arranged to determine whether a voltage difference between a second specific voltage and the first specific voltage is larger than a threshold value, wherein the second specific voltage is selected from the first voltage and the second voltage, and when the voltage difference is larger than the threshold value, the protection circuit controls the current regulating circuit to stop conducting current to a specific pin corresponding to the first specific voltage, so as to make a voltage of the specific pin no longer the first specific voltage.