Gate driving circuit and display device including the same
A display device can include a display panel having a plurality of sub-pixels disposed thereon, and a gate driving circuit configured to output a gate signal to the plurality of sub-pixels. The gate driving circuit includes a pull-up transistor controlled by a voltage level of a Q-node, a pull-down transistor configured by a voltage level of a QB-node, a pump capacitor electrically connected between the Q-node and a clock signal input terminal, a pump transistor electrically connected between the pump capacitor and the Q-node and controlled by the gate signal output to a gate line, a clock transistor electrically connected between the pump capacitor and the clock signal input terminal and controlled by a voltage level of a start signal input node, and a direction selection circuit configured to output a forward start signal or a backward start signal to the start signal input node.
1 . A display device comprising:
a display panel including a plurality of sub-pixels disposed thereon; and
a gate driving circuit configured to output a gate signal to the plurality of sub-pixels,
wherein the gate driving circuit comprises:
a pull-up transistor controlled by a voltage level of a Q-node;
a pull-down transistor configured by a voltage level of a QB-node;
a pump capacitor electrically connected between the Q-node and an input terminal for an AC signal;
a pump transistor electrically connected between the pump capacitor and the Q-node and controlled by the gate signal output to a gate line;
a clock transistor electrically connected between the pump capacitor and the input terminal for the AC signal and controlled by a voltage level of a start signal input node;
a first transistor electrically connected between the Q-node and the start signal input node and controlled by a voltage level of a clock signal;
a direction selection circuit configured to output a forward start signal or a backward start signal to the start signal input node; and
a feed transistor including a gate connected to an output terminal from which the gate signal is output, a first electrode connected to a gate of the pump transistor, and a second electrode connected to an input terminal for a low drive voltage, and
wherein the AC signal has a cycle corresponding to 1/N of a cycle of the clock signal, where N is a multiple of 2.
2 . The display device according to claim 1 , wherein the direction selection circuit applies the forward start signal to the start signal input node when a forward low voltage is input thereto, and applies the backward start signal to the start signal input node when a backward low voltage is input thereto.
3 . The display device according to claim 2 , wherein the direction selection circuit comprises:
a forward direction selection transistor connected between a line for the forward start signal and the start signal input node, the forward direction selection transistor comprising a gate configured to receive the forward low voltage; and
a backward direction selection transistor connected between a line for the backward start signal and the start signal input node, the backward direction selection transistor comprising a gate configured to receive the backward low voltage.
4 . The display device according to claim 1 , wherein a gate node of the pump transistor is electrically connected to a node between the pump transistor and the pump capacitor.
5 . The display device according to claim 1 , wherein the display panel comprises a substrate on which the gate driving circuit is disposed at least one in number among pixel areas formed with the plurality of sub-pixels.
6 . The display device according to claim 1 , wherein each of the plurality of sub-pixels comprises:
a light emitting element;
a driving transistor configured to supply a drive current to the light emitting element; and
a plurality of switching transistors configured to control driving timings of the driving transistor and the light emitting element, and
wherein the gate signal is supplied to control, among the plurality of plurality of switching transistor, a switching transistor configured to control a turn-on period of the light emitting element.
7 . A gate driving circuit comprising:
a pull-up transistor controlled by a voltage level of a Q-node, and electrically connected between an input terminal for a low drive voltage and an output terminal for a gate signal;
a pull-down transistor controlled by a voltage level of a QB-node, and electrically connected between an input terminal for a high drive voltage and the output terminal for the gate signal;
a pump capacitor electrically connected between the Q-node and an input terminal for an AC signal;
a pump transistor electrically connected between the pump capacitor and the Q-node and controlled by the gate signal output to a gate line;
a clock transistor electrically connected between the pump capacitor and the input terminal for the AC signal, and controlled by a voltage level of a start signal input node;
a first transistor electrically connected between the Q-node and the start signal input node, and controlled by a voltage level of a gate clock signal;
a direction selection circuit configured to output a forward start signal or a backward start signal to the start signal input node; and
a feed transistor including a gate connected to an output terminal from which the gate signal is output, a first electrode connected to a gate of the pump transistor, and a second electrode connected to the input terminal for the low drive voltage, and
wherein the AC signal has a cycle corresponding to 1/N of a cycle of the gate clock signal, where N is a multiple of 2.
8 . The gate driving circuit according to claim 7 , wherein the direction selection circuit comprises:
a forward direction selection transistor connected between a line for the forward start signal and the start signal input node, the forward direction selection transistor comprising a gate configured to receive a forward low voltage; and
a backward direction selection transistor connected between a line for the backward start signal and the start signal input node, the backward direction selection transistor comprising a gate configured to receive a backward low voltage.
9 . A display device comprising:
a display panel including a plurality of sub-pixels disposed thereon; and
a gate driving circuit configured to output a gate signal to the plurality of sub-pixels,
wherein the gate driving circuit comprises:
a pull-up transistor controlled by a voltage level of a Q-node;
a pull-down transistor configured by a voltage level of a QB-node;
a pump capacitor electrically connected between the Q-node and an input terminal for an AC signal;
a pump transistor electrically connected between the pump capacitor and the Q-node and controlled by the gate signal output to a gate line;
a clock transistor electrically connected between the pump capacitor and the input terminal for the AC signal and controlled by a voltage level of a start signal input node;
a first transistor electrically connected between the Q-node and the start signal input node and controlled by a voltage level of a clock signal;
a direction selection circuit configured to output a forward start signal or a backward start signal to the start signal input node; and
a feed transistor including a gate connected to an output terminal from which the gate signal is output, a first electrode connected to a gate of the pump transistor, and a second electrode connected to an input terminal for a low drive voltage, and
wherein the AC signal has a cycle corresponding to 1/N of a cycle of the clock signal, where N is a multiple of 2.
10 . The display device according to claim 9 , wherein the direction selection circuit comprises:
a forward direction selection transistor connected between a line for the forward start signal and the start signal input node, the forward direction selection transistor comprising a gate configured to receive a forward low voltage; and
a backward direction selection transistor connected between a line for the backward start signal and the start signal input node, the backward direction selection transistor comprising a gate configured to receive a backward low voltage.
11 . The display device according to claim 9 , wherein a voltage of the Q-node is boosted when the forward start signal or the backward start signal is applied at a low level, the clock signal is applied at a low level, and the AC signal has a low level.
12 . The display device according to claim 9 , wherein a voltage level of the Q-node is varied at a time when the AC signal transitions from a high level to a low level.