Apparatus for driving light emitting diode array and liquid crystal display device using the same

1. An apparatus for driving a light emitting diode (LED) array, comprising:

a current amount setter configured to vary a voltage at a node or a current in the node of the current amount setter according to a selection signal from an external system; and

a controller coupled to the current amount setter and the LED array, the controller comprising:

a power supplier connected to the node of the current amount setter and configured to adjust a level of current provided to the LED array based on an input voltage received from the external system and the voltage at the node or the current in the node of the current amount setter, and

a signal supplier configured to distribute direct current (DC) signals remaining unchanged during a frame cycle to a plurality of switches coupled to the LED array to turn on or off LEDs in the LED array.

2. The apparatus of claim 1 , wherein the current amount setter comprises a selection terminal connected to the external system, a resistance across the current amount setter determined based on connection of the selection terminal to a high-level voltage terminal or a ground terminal through the external system or being maintained in a high impedance state.

3. The apparatus of claim 1 , wherein the current amount setter comprises:

a capacitor between the node and a low reference voltage;

a transistor having a gate coupled to the selection terminal;

a diode between a source of the transistor and the selection terminal;

a first resistor between the source of the transistor and the node;

a second resistor between the source of the transistor and the low reference voltage; and

a third resistor between a drain of the transistor and the low reference voltage.

4. The apparatus of claim 1 , wherein the current amount setter comprises at least two selection terminals connected to a ground terminal or maintained in an high impedance state, the resistance across the current amount setter determined based on connection of the selection terminals to the ground terminal through the external system or being maintained in a high impedance state.

5. The apparatus of claim 4 , wherein the current amount setter comprises a string of resistors connected in parallel to a capacitor, each of the at least two selection terminals connected between the string of resistors.

6. The apparatus of claim 1 , wherein the plurality of switching transistors are connected between a ground terminal and a plurality of LED strings in the LED array.

7. The apparatus of claim 1 , wherein the signal supplier is configured to distribute the DC signals to the plurality of switches responsive to receiving a DC signal from the external system.

8. The apparatus of claim 1 , wherein the LED array comprises a plurality of strings of LEDs, each string of LEDs coupled to a low reference voltage via each of the plurality of switches.

9. A liquid crystal display (LCD) device including an apparatus for driving a light emitting diode (LED) array, the LCD device comprising:

a panel in which a plurality of pixels are respectively formed in a plurality of areas defined by intersections between a plurality of gate lines and a plurality of data lines, the panel irradiated by light from the LED array;

a driver configured to control signals to be supplied to the gate lines and the data lines; and

an LED array driving apparatus comprising:

a current amount setter configured to vary a voltage at a node or a current in the node of the current amount setter according to a selection signal from an external system; and

a controller coupled to the current amount setter and the LED array, the controller comprising:

a power supplier configured to adjust a level of current provided to the LED array based on an input voltage received from the external system and the resistance across the current amount setter, and

a signal supplier configured to distribute direct current (DC) signals remaining unchanged during a frame cycle to a plurality of switches coupled to the LED array to turn on or off LEDs in the LED array.

10. The LCD device of claim 9 , wherein the current amount setter comprises a selection terminal connected to the external system, a resistance across the current amount setter determined based on connection of the selection terminal to a high-level voltage terminal or a ground terminal through the external system or being maintained in a high impedance state.

11. The LCD device of claim 9 , wherein the current amount setter comprises:

a capacitor between the node and a low reference voltage;

a transistor having a gate coupled to the selection terminal;

a diode between a source of the transistor and the selection terminal;

a first resistor between the source of the transistor and the node;

a second resistor between the source of the transistor and the low reference voltage; and

a third resistor between a drain of the transistor and the low reference voltage.

12. The LCD device of claim 9 , wherein the current amount setter comprises at least two selection terminals connected to a ground terminal or maintained in an high impedance state, the resistance across the current amount setter determined based on connection of the selection terminals to the ground terminal through the external system or being maintained in a high impedance state.

13. The LCD device of claim 12 , wherein the current amount setter comprises a string of resistors connected in parallel to a capacitor, each of the at least two selection terminals connected to a node between the string of resistors.

14. The LCD device of claim 9 , wherein the plurality of switching transistors are connected between a ground terminal and a plurality of LED strings in the LED array.

15. The LCD device of claim 9 , wherein the signal supplier is configured to distribute the DC signals to the plurality of switches responsive to receiving a DC signal from the external system.

16. The LCD device of claim 9 , wherein the LED array comprises a plurality strings of LEDs, each string of LEDs coupled to a low reference voltage via each of the plurality of switches.