Shift register unit, gate drive circuit having the same, and driving method thereof

1. A shift register unit circuit comprising an input port for receiving an input signal, an output port for outputting a gate driving signal, a first clock input port for receiving a first clock signal, a second clock input port for receiving a second clock signal, a pull-up node, a first pull-down node, and a second pull-down node;

the shift register unit circuit further comprising:

a pull-up control sub-circuit connected to the input port and the pull-up node, the pull-up control sub-circuit being configured to control a potential level at the pull-up node based on the input signal received from the input port;

a pull-up sub-circuit connected to the first clock input port and the pull-up node, the pull-up sub-circuit being configured to output an output signal from the output port based on the first clock signal and the potential level at the pull-up node, the output signal being used as the gate driving signal;

a pull-down control sub-circuit connected to the first clock input port, the second clock input port, and the pull-up node, the pull-down control sub-circuit being configured to control potential levels respectively at the first pull-down node and the second pull-down node based on the first clock signal, the second clock signal, and the potential level at the pull-up node;

a pull-down sub-circuit connected to the first pull-down node and the second pull-down node, the pull-down sub-circuit being configured to pull down respective potential levels at the output port and the pull-up node based on the potential levels of the first pull-down node and the second pull-down node;

a reset sub-circuit connected to a reset port for receiving a reset signal to control the potential level at the second pull-down node; and

an initialization sub-circuit configured to receive an enabling signal for pulling-down the potential level at the second pull-down node to a potential level of a fixed low potential terminal;

wherein the pull-down control sub-circuit is configured to maintain the potential levels of the first pull-down node and the second pull-down node at logic low when the potential level of the pull-up node is set to logic high.

2. The shift register unit circuit of claim 1 , wherein the reset sub-circuit includes a diode having an anode connected to the reset port and a cathode connected to the second pull-down node.

3. The shift register unit circuit of claim 1 , wherein the initialization sub-circuit includes a transistor having a gate receiving the enabling signal, a first terminal connected to the second pull-down node and a second terminal connected to the fixed low potential terminal.

4. The shift register unit circuit of claim 1 , wherein the first clock signal and the second clock signal are alternatively provided with a logic high potential and a logic low potential with a substantially same frequency and amplitude but in reversed phase.

5. The shift register unit circuit of claim 4 , wherein the pull-down control sub-circuit is configured, under a condition that the potential level of the pull-up node is set at logic high, to maintain the potential level of the second pull-down node at logic low whenever the first clock signal is provided with a logic low potential.

6. The shift register unit circuit of claim 4 , wherein the pull-down control sub-circuit is configured, under a condition that the potential level of the pull-up node is set at logic high, to maintain the potential level of the first pull-down node at logic low whenever the second clock signal is provided with a logic low potential.

7. The shift register unit circuit of claim 4 , wherein the pull-down control sub-circuit comprises a first transistor, a second transistor, a third transistor, and a fourth transistor; wherein the first transistor has a first terminal connected to the second clock input port and a second terminal connected to the first pull-down node; wherein the second transistor has a first terminal and a control terminal commonly connected to the second clock input port and a second terminal connected to a control terminal of the first transistor; wherein the third transistor has a first terminal connected to the first pull-down node and a control terminal connected to the pull-up node; wherein the fourth transistor has a first terminal connected to the second terminal of the second transistor, a control terminal connected to the pull-up node.

8. The shift register unit circuit of claim 7 , wherein the pull-down control sub-circuit further comprising a fifth transistor and a diode, the fifth transistor having a first terminal connected to the first clock input port, a control terminal connected to the second terminal of the second transistor, the diode having an anode connected to a second terminal of the fifth transistor and a cathode connected to the second pull-down node.

9. The shift register unit circuit of claim 8 , wherein the pull-down sub-circuit further comprising a sixth transistor, a seventh transistor, an eighth transistor, and a ninth transistor; wherein the sixth transistor has a gate connected to the second pull-down node and a drain connected to the pull-up node; wherein the seventh transistor has a gate connected to the second pull-down node and a drain connected to the output port; wherein the eighth transistor has a gate connected to the first pull-down node and a drain connected to the pull-up node; wherein the ninth transistor has a gate connected to the first pull-down node and a drain connected to the output port.

10. The shift register unit circuit of claim 7 , wherein the logic high potential corresponds to a voltage signal that is applied to a gate of any transistor in claim 7 for turning the transistor in a conduction state, the logic low potential corresponds to a voltage signal that is applied to a gate of any transistor in claim 7 for turning the transistor in a blocking-state.

11. A gate drive circuit comprising N numbers of shift register units of claim 1 cascaded in series from a first shift register unit to a N-th shift register unit, N being a natural integer greater than 1, wherein an n-th shift register unit, except the first shift register unit, is configured to have an input port connected to an output port of a previous adjacent (n−1)-th shift register unit, n being a natural integer and 1<n≤N; wherein the first shift register unit has an input port connected to an initialization receiving an enabling signal.

12. A display apparatus comprising a display panel, a data drive circuit, and a gate drive circuit of claim 11 configured to output a plurality of gate drive signals to control a plurality of rows of transistors associated with an array of pixels disposed on the display panel for displaying image based on respective a plurality of image data provided by the data drive circuit.

13. A method for driving the shift register unit circuit, wherein the shift register unit comprises:

a pull-up control sub-circuit connected to an input port and a pull-up node;

a pull-up sub-circuit connected to a first clock input port and the pull-up node for controlling an output port to output an output signal;

a pull-down control sub-circuit connected to a first clock input port, a second clock input port, and the pull-up node;

a pull-down sub-circuit connected to a first pull-down node and a second pull-down node;

a reset sub-circuit connected to a reset port and the second pull-down node; and

an initialization sub-circuit connected to an initialization port and the second pull-down node and a low potential level terminal;

the method comprising:

controlling a potential level of the pull-up node via the pull-up control sub-circuit based on an input signal received at the input port;

outputting an output signal from the output port controlled by the pull-up sub-circuit based on a first clock signal provided at the first clock input port and the potential level of the pull-up node;

controlling potential levels of the first pull-down node and the second pull-down node via the pull-down control sub-circuit based on the first clock signal, a second clock signal provided at the second clock input port, and the potential level of the pull-up node;

pulling down potential levels of the output port and the pull-up node controlled by the pull-down sub-circuit based on the potential level of the first pull-down node and/or the potential level of the second pull-down node;

wherein controlling potential levels of the first pull-down node and the second pull-down node comprises maintaining the potential level of the first pull-down node or the second pull-down node to be logic high when the potential level of the pull-up node is at logic low.

14. The method of claim 13 , further comprising controlling a potential level of the second pull-down node to logic high based on a reset signal received at the reset port by the reset sub-circuit via a diode.

15. The method of claim 13 , further comprising pulling down the potential level of the second pull-down node to logic low based on an enabling signal at logic high received from the initialization port connected to the initialization sub-circuit through a gate of a transistor, the transistor having a source connected to the second pull-down node and a drain connected to a fixed low potential terminal.

16. The method of claim 13 , wherein the first clock signal and the second clock signal are alternatively provided with a logic high potential and a logic low potential with a substantially same frequency and amplitude but in reversed phase.

17. The method of claim 16 , wherein controlling potential levels of the first pull-down node and the second pull-down node comprises, under a condition that the potential level of the pull-up node is set at logic high, maintaining the potential level of the second pull-down node at logic low whenever the first clock signal is provided with a logic low potential.

18. The method of claim 16 , wherein controlling potential levels of the first pull-down node and the second pull-down node comprises, under a condition that the potential level of the pull-up node is set at logic high, maintaining the potential level of the first pull-down node at logic low whenever the second clock signal is provided with a logic low potential.