Gate driver and electroluminescence display device including the same

1. An electroluminescent display device comprising:

sub-pixels connected to gate lines; and

a gate driver configured to supply a scan signal to at least one of the gate lines, and including stages,

wherein one of the stages comprises:

a QB-node regulation unit configured to charge a QB-node and a QP-node to turn-on voltage by using a first gate clock signal and a second gate clock signal; and

a pull-down unit configured to output a turn-off voltage in response to a voltage of the QP-node, and

wherein the QB-node regulation unit comprises:

a QP-node control part configured to invert a phase of a voltage of a Q1-node and apply the voltage of the inverted phase to the QP-node; and

a QB-node control part configured to bootstrap the QP-node.

2. The electroluminescent display device of claim 1 , wherein the QP-node control part comprises:

a first transistor connected between a gate-low voltage line and the QP-node, and having a gate electrode connected to a second gate clock signal line; and

a second transistor connected between the second gate clock signal line and the QP-node, and having a gate electrode connected to the Q1-node, and

wherein the QB-node control unit comprises

a third transistor connected between a first gate clock signal line and the QB-node, and having a gate electrode connected to the QP-node; and

a first capacitor connected between the QP-node and the QB-node.

3. The electroluminescent display device of claim 1 , wherein the one of the stages further comprises:

a Q1-node control unit discharging the Q1-node to a turn-off voltage in response to the voltage of QB-node, and applying a gate-start voltage to the Q1-node in response to the second gate clock signal.

4. The electroluminescent display device of claim 3 , wherein the Q1-node control unit comprises:

a fourth transistor connected between a gate-start voltage line to which the gate-start voltage is applied and the Q1-node, and having a gate electrode connected to a second gate clock signal line; and

a fifth transistor connected between the Q1-node and a gate-high voltage line, and having a gate electrode connected to the QB-node.

5. The electroluminescent display device of claim 1 , wherein the one of the stages further comprises:

a pull-up unit outputting the turn-on voltage in response to the voltage of the Q2-node.

6. The electroluminescent display device of claim 5 , wherein the pull-up unit comprises a sixth transistor connected between a first gate clock signal line and the scan signal output line, and having a gate electrode connected to the Q2-node, and

wherein the pull-down unit comprises a seventh transistor connected between a gate-high voltage line and the scan signal output line, and having a gate electrode connected to the QP-node.

7. The electroluminescent display device of claim 5 , wherein the one of the stages further comprises a Q-node stabilization unit connected between the Q1-node and the Q2-node.

8. The electroluminescent display device of claim 1 , wherein the one of the stages further comprises a QB-node stabilization unit discharging the QB-node to the turn-off voltage in response to the voltage of the Q1-node.

9. A gate driver comprising:

a pull-up transistor having a gate electrode connected to a Q2-node to output a turn-on voltage;

a pull-down transistor having a gate electrode connected to a QP-node to output a turn-off voltage; and

a QB-node regulation unit configured to periodically provide a voltage greater than the turn-on voltage to the QP-node and periodically provide the turn-on voltage to a QB-node, with the turn-off voltage applied to the gate electrode of the pull-up transistor,

wherein the QB-node regulation unit comprises:

a third transistor connected between a first gate clock signal line and the QB-node and having a gate electrode connected to the QP-node; and

a first capacitor connected between the QP-node and the QB-node.

10. The gate driver of claim 9 , further comprising:

a Q-node stabilization unit connected between the Q2-node and a Q1-node;

a Q1-node activator applying a gate-start voltage to the Q1-node; and

a Q1 -node discharger periodically discharging the Q1-node in response to a voltage of the QB-node.

11. The gate driver of claim 10 , further comprising:

a QB-node stabilization unit discharging the QB-node in response to the voltage of the Q1-node.

12. The gate driver of claim 10 , wherein the QB-node regulation unit further comprises:

a first transistor connected between a gate-low voltage line and the QP-node and having a gate electrode connected to a second gate clock signal line; and

a second transistor connected between the second gate clock signal line and the QP-node and having a gate electrode connected to the Q1-node,

wherein the first gate clock signal and the second gate clock signal are in reversed phase.

13. The gate driver of claim 10 , wherein a voltage of the QP-node and the voltage of the QB-node are the turn-off voltage, and the pull-up transistor is turned on to output the turn-on voltage while a voltage of the Q2-node is greater than the turn-on voltage.

14. The gate driver of claim 9 , further comprising:

a second capacitor connected between the gate electrode and a drain electrode of the pull-up transistor.

15. The gate driver of claim 14 , further comprising:

an eighth transistor connected between the Q2-node and the Q1-node and having a gate electrode connected to a line to which the turn-on voltage is applied, wherein the eighth transistor is turned off while the voltage greater than the turn-on voltage is applied to the Q2-node by the second capacitor.