Shift register and control method thereof

A shift register, comprising:

• a first input end;
• a second input end;
• a first switch, having a first end, a second end and a control end, the first end receiving a first clock signal, the second end being coupled to an output end of the shift register, and the control end being coupled to a first node;
• a pull-up circuit, comprising:
• a second switch, having a first end, a second end and a control end, the first end of the second switch being coupled to a first system power terminal, and the control end of the second switch being coupled to the first input end;
• and
• a first control circuit, configured to control electrical connection between the second end of the second switch and the first node according to a voltage level of the first system power terminal;
• and
• a pull-down circuit, comprising:
• a third switch, a first end of the third switch being coupled to the first node, a second end of the third switch being coupled to the output end of the shift register, and a control end of the third switch being coupled to a second node;
• a second control circuit, configured to control electrical connection between the first system power terminal and a third node according to the first clock signal and configured to control electrical connection between the first system power terminal and a fourth node according to a second clock signal;
• a third control circuit, configured to control electrical connection between a second system power terminal and the second node and electrical connection between the second system power terminal and the third node according to a voltage level of the first input end;
• a fourth switch, a first end of the fourth switch being coupled to the fourth node, a second end of the fourth switch being coupled to the second node, and a control end of the fourth switch being coupled to the third node;
• a fifth switch, a first end of the fifth switch being coupled to the fourth node, a second end of the fifth switch being coupled to the second system power terminal, and a control end of the fifth switch being coupled to the output end of the shift register;
• a sixth switch, a first end of the sixth switch being coupled to the output end of the shift register, a second end of the sixth switch being coupled to the second system power terminal, and a control end of the sixth switch being coupled to the second node;
• and
• a seventh switch, a first end of the seventh switch being coupled to the output end of the shift register, a second end of the seventh switch being coupled to the second system power terminal, and a control end of the seventh switch being coupled to the second input end.