Shift Register Unit, Drive Method Thereof, Gate Drive Device, and Display Device

A gate drive device, comprising cascaded N shift register units, the N shift register units are those from the first shift register unit to the Nth shift register unit, wherein N is a natural number;

• the signal input end of each shift register unit from the second shift register unit to the Nth shift register unit is connected with the output end of the shift register unit at the previous stage;
• the reset signal end of each shift register unit from the first shift register unit to the N- lth shift register unit is connected with the output end of the shift register unit at the next stage,
• the signal input end of the first shift register unit is connected with a frame start signal, and the reset signal end of the Nth shift register is connected with the frame start signal end.,
• each of the shift register unit, comprising:
• an input sub-circuit, connecting a signal input end, a high-level voltage signal end and a pull-up node, is configured to provide the high-level voltage signal for the pull-up node in response to an input signal of the signal input end;
• a reset sub-circuit, connecting a reset signal end, a first low-level voltage signal end and the pull-up node, is configured to provide a first low-level voltage signal for the pull-up node in response to the reset signal of the reset signal end;
• an output sub-circuit, connecting a clock signal end, a control signal end, the pull-up node, a pull-down sub-circuit and an output end at the current stage, is configured to provide a clock signal outputted by the clock signal end for an output end of the shift register unit at the current stage in response to a voltage signal of the pull-up node and a control signal of a first level;
• and to make the output end at the current stage have no output to scan the touch signal in response to the control signal of the second level;
• a pull-down controlling sub-circuit, connecting the high-level voltage signal end, the pull-up node, a second low-level voltage signal end and the pull-down node, is configured to provide the second low-level voltage signal for the pull-down node in response to a voltage signal of the pull-up node, and to provide the high-level voltage signal for the pull-down node in response to the high-level voltage signal;
• a pull-down sub-circuit, connecting the second low-level voltage signal end, the pull-down node and the output end at the current stage, is configured to provide the second low-level voltage signal for the pull-up node and the output end at the current stage in response to the voltage signal of the pull-down node.

A drive method for a shift register unit, which includes an input sub-circuit, a reset sub-circuit, an output sub-circuit, a pull-down controlling sub-circuit, a pull-down sub-circuit, wherein the input sub-circuit connects a signal input end, a high-level voltage signal end and a pull-up node, the reset sub-circuit connects the reset signal end, a first low-level voltage signal end and a pull-up node, the output sub-circuit connects a clock signal end, a control signal end, the pull-up node and an output end at the current stage, the pull-down controlling sub-circuit connects the high-level voltage signal end, pull-up node, a second low-level voltage signal end and a pull-down node, and the pull-down sub-circuit connects the second low-level voltage signal end, the pull-down node, the pull-up node and the output end at the current stage;

• the drive method includes:
• in the first phase, after receiving a signal of the signal input end, the input sub-circuit pulls the potential of the pull-up node up to a high level of the high-level voltage signal end;
• after receiving the high-level voltage signal outputted by the pull-up node, the pull-down controlling sub-circuit pulls the potential of the pull-down node down to the low level;
• in the first mode of the second phase, when the control signal is a first level, the output sub-circuit provides a clock signal outputted from the clock signal end for the output end of the shift register unit after receiving the high-level voltage signal outputted from the pull-up node;
• and
• the pull-down controlling sub-circuit still holds the low level of the pull-down node;
• in the second mode of the second phase, when the control signal is a second level, the output sub-circuit has no output so that the reset sub-circuit has no input of the reset signal, thereby scanning the touch signal during this period;
• in the third phase, after receiving the reset signal of the reset signal end, the reset sub-circuit pulls the pull-up node down to the low level;
• after receiving the high-level voltage signal outputted by the high-level voltage signal end, the pull-down controlling sub-circuit pulls the pull-down node up to the high level;
• after receiving the high level outputted by the pull-down node, the pull-down sub-circuit pulls the output end and the pull-up node of the shift register down to the second low-level voltage;
• in the fourth phase, when the input sub-circuit has no input signal, the pull-down controlling sub-circuit makes the pull-down node keep the high potential;
• after receiving the high level outputted by the pull-down node, the pull-down sub-circuit pulls the output end and pull-up node of the shift register down to the second low-level voltage.