SCAN DRIVING CIRCUIT AND LCD DEVICE

• US 20160284304A1
• Filed: 06/25/2014
• Published: 09/29/2016
• Est. Priority Date: 05/20/2014
• Status: Active Grant

• Current Assignee: Shenzhen China Star Optoelectronics Technology Co., Ltd. (TCL Technology Group Corp.)
• Original Assignee: Shenzhen China Star Optoelectronics Technology Co., Ltd. (TCL Technology Group Corp.)
• Inventors: DAI, Chao
• Granted Patent: US 9,530,372 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G09G 2300/0408 Integration of the drivers onto the display substrate
• CPC Class Codes: G09G 2310/06 Details of flat display driving waveforms
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 3/36 using liquid crystals
• CPC Class Codes: G09G 3/3677 suitable for active matrices only

Abstract

A scan driving circuit and a liquid crystal display device include a pull-up assembly, a pull-up control assembly that drives the pull-up assembly, a pull-down maintaining assembly, a reference low-level signal, and a down-transmitting assembly. A control end of the down-transmitting assembly is coupled to an output end of the pull-up control assembly and a control end of the pull-up assembly, and a current down-transmitting signal is output from an output end of the down-transmitting assembly.

Claims

1. A scan driving circuit, comprising:

a pull-up assembly;

a pull-up control assembly that drives the pull-up assembly;

a pull-down maintaining assembly;

a reference low-level signal;

a pull-down maintaining signal; and

a down-transmitting assembly;

wherein an output end of the pull-up assembly is coupled to a current scanning line, and the reference low-level signal is sent to the output end of the pull-up control assembly and the current scanning line via the pull-down maintaining assembly;

the pull-down maintaining signal is sent to a control end of the pull-down maintaining assembly;

a control end of the down-transmitting assembly is coupled to the output end of the pull-up control assembly and a control end of the pull-up assembly, and a current down-transmitting signal is output from an output end of the down-transmitting assembly.

2. The scan driving circuit of claim 1, wherein the pull-down maintaining assembly comprises a first pull-down maintaining assembly and a second pull-down maintaining assembly;

input ends of the first pull-down maintaining assembly and the second pull-down maintaining assembly are coupled to the output end of the pull-up control assembly, the pull-down maintaining signal is sent to control ends of the first pull-down maintaining assembly and the second pull-down maintaining assembly, and the reference low-level signal is sent to output ends of the first pull-down maintaining assembly and the second pull-down maintaining assembly;

the scan driving circuit further comprises a diverter switch connected between the control ends of the first pull-down maintaining assembly and the second pull-down maintaining assembly, and a control end of the diverter switch is coupled to the output end of the pull-up control assembly;

when the current scanning line is active, the diverter switch turns off the first pull-down maintaining assembly and the second pull-down maintaining assembly, and the reference low-level signal is not sent to the output end of the pull-up control assembly and the current scanning line.

3. The scan driving circuit of claim 1, wherein the pull-down maintaining assembly comprises a first pull-down maintaining assembly, and the first pull-down maintaining assembly comprises a first pull-down maintaining unit and a first pull-down maintaining control unit that drives the first pull-down maintaining unit;

the first pull-down maintaining unit comprises a first controllable switch and a second controllable switch;

the pull-down maintaining signal comprises a first pull-down maintaining signal, and the first pull-down maintaining signal is sent to control ends of the first controllable switch and the second controllable switch via the first pull-down maintaining control unit;

the reference low-level signal is sent to the current scanning line via the first controllable switch, and is sent to the output end of the pull-up control assembly via the second controllable switch;

the down-transmitting assembly comprises a nineteenth controllable switch, a control end of the nineteenth controllable switch is coupled to the output end of the pull-up control assembly and the control end of the pull-up assembly, a clock scanning signal is sent to an input end of the nineteenth controllable switch, and the current down-transmitting signal is output from an output end of the nineteenth controllable switch;

the first pull-down maintaining unit further comprises a seventh controllable switch;

a control end of the seventh controllable switch is coupled to the control ends of the first and second controllable switches, an input end of the seventh controllable switch is coupled to the output end of the nineteenth controllable switch, and the reference low-level signal is sent to an output end of the seventh controllable switch;

when the current scanning line is inactive, the first pull-down maintaining control unit controls the first controllable switch, the second controllable switch, and the seventh controllable switch to turn on according to the first pull-down maintaining signal, and the first controllable switch controls the reference low-level signal to be sent to the current scanning line, the second controllable switch controls the reference low-level signal to be sent to the output end of the pull-up control assembly, and the seventh controllable switch controls the reference low-level signal to be sent to the output end of the nineteenth controllable switch;

when the current scanning line is active, the first pull-down maintaining control unit controls the first controllable switch and the second controllable switch to turn off according to the first pull-down maintaining signal;

the first controllable switch controls the reference low-level signal to be not sent to the current scanning line, the second controllable switch controls the reference low-level signal to be not sent to the output end of the pull-up control assembly, and the seventh controllable switch controls the reference low-level signal to be not sent to the output end of the nineteenth controllable switch.

4. The scan driving circuit of claim 3, wherein the first pull-down maintaining control unit comprises a third controllable switch, a fourth controllable switch, and a fifth controllable switch;

the pull-down maintaining signal further comprises a second pull-down maintaining signal, and logical operation of the second pull-down maintaining signal is opposite to logical operation of the first pull-down maintaining signal;

the third controllable switch uses diode connection method, the first pull-down maintaining signal is sent to an input end and a control end of the third controllable switch;

an output end of the third controllable switch is coupled to a control end of the fourth controllable switch;

the first pull-down maintaining signal is sent to an input end of the fourth controllable switch, and an output end of the fourth controllable switch is coupled to the control ends of the first and second controllable switches;

the second pull-down maintaining signal is sent to a control end of the fifth controllable switch, the first pull-down maintaining signal is sent to an input end of the fifth controllable switch, and an output end of the fifth controllable switch is coupled to the control ends of the first and second controllable switches.

5. The scan driving circuit of claim 4, wherein the pull-down maintaining assembly further comprises a turn-off unit, and the turn-off unit comprises a sixth controllable switch;

a control end of the sixth controllable switch is coupled to the output end of the pull-up control assembly, an input end of the sixth controllable switch is coupled to the control end of the fourth controllable switch, and the reference low-level signal is sent to an output end of the sixth controllable switch.

6. The scan driving circuit of claim 4, wherein the pull-down maintaining assembly further comprises a turn-off unit, and the turn-off unit comprises a sixth controllable switch;

a control end of the sixth controllable switch is coupled to the output end of the pull-up control assembly, an input end of the sixth controllable switch is coupled to the control end of the fourth controllable switch, and the second pull-down maintaining signal is sent to an output end of the sixth controllable switch.

7. The scan driving circuit of claim 3, wherein the pull-down maintaining assembly further comprises a second pull-down maintaining assembly comprising a second pull-down maintaining unit and a second pull-down maintaining control unit, the second pull-down maintaining control unit drives the second pull-down maintaining unit;

the pull-down maintaining signal comprises a second pull-down maintaining signal, logical operation of the second pull-down maintaining signal is opposite to logical operation of the first pull-down maintaining signal;

the second pull-down maintaining unit comprises an eighth controllable switch and a ninth controllable switch;

the second pull-down maintaining signal is sent to control ends of the eighth and ninth controllable switches via the second pull-down maintaining control unit;

the reference low-level signal is sent to the current scanning line via the eighth controllable switch, and is sent to the output end of the pull-up control assembly via the ninth controllable switch;

when the current scanning line is inactive, the first pull-down maintaining unit and the second pull-down maintaining unit alternately turn on;

when the second pull-down maintaining unit turn on, the eighth and ninth controllable switches turn on, and the reference low-level signal is sent to the output end of the pull-up control assembly and the current scanning line;

when the current scanning line is active, the first pull-down maintaining unit and the second pull-down maintaining unit turn off, and the first, second, eighth, and ninth controllable switches turn off, and the reference low-level signal is not sent to the output end of the pull-up control assembly and the current scanning line.

8. The scan driving circuit of claim 7, wherein the second pull-down maintaining control unit comprises a tenth controllable switch, an eleventh controllable switch, and a twelfth controllable switch;

the tenth controllable switch uses diode connection method, the second pull-down maintaining signal is sent to an input end and a control end of the tenth controllable switch;

an output end of the tenth controllable switch is coupled to a control end of the eleventh controllable switch;

the second pull-down maintaining signals is sent to an input end of the eleventh controllable switch, and an output end of the eleventh controllable switch is coupled to the control ends of the eighth and ninth controllable switches;

the first pull-down maintaining signal is sent to a control end of the twelfth controllable switch, the second pull-down maintaining signal is sent to an input end of the twelfth controllable switch, and an output end of the twelfth controllable switch is coupled to the control ends of the eighth and ninth controllable switches;

when the current scanning line is inactive and the second pull-down maintaining assembly turns on, the tenth, eleventh, and twelfth controllable switches control the eighth and ninth controllable switches to turn on according to the first and second pull-down maintaining signals, and the reference low-level signal is sent to the output end of the pull-up control assembly and the current scanning line.

9. The scan driving circuit of claim 7, wherein the reference low-level signal comprises a first reference low-level signal and a second reference low-level signal;

electric potential of the second reference low-level signal is less than electric potential of the first reference low-level signal, and electric potential of the pull-down maintaining signal at low level is less than electric potential of the second reference low-level signal;

the first reference low-level signal is sent to the current scanning line via the eighth controllable switch, and the second reference low-level signal is sent to the output end of the pull-up control assembly via the ninth controllable switch;

when the current scanning line is inactive and the second pull-down maintaining assembly turns on, the eighth controllable switch and the ninth controllable switch turn on, and the eighth controllable switch controls the first reference low-level signal to be sent to the current scanning line, the ninth controllable switch controls the second reference low-level signal to be sent to the output end of the pull-up control assembly.

10. The scan driving circuit of claim 7, wherein the pull-down maintaining assembly further comprises a turn-off unit, and the turn-off unit comprises a thirteenth controllable switch;

the reference low-level signal comprises a first reference low-level signal and a second reference low-level signal;

electric potential of the second reference low-level signal is less than electric potential of the first reference low-level signal, and electric potential of the pull-down maintaining signal at low level is less than electric potential of the second reference low-level signal;

the first reference low-level signal is sent to the current scanning line via the eighth controllable switch, and the second reference low-level signal is sent to the output end of the pull-up control assembly via the ninth controllable switch;

an input end of the thirteenth controllable switch is coupled to the control ends of the eighth controllable switch and the ninth controllable switch, the first reference low-level signal, the second reference low-level signal, or the second pull-down maintaining signal is sent to an output end of the thirteenth controllable switch;

the first reference low-level signal is sent to the output end of the first controllable switch, and the second reference low-level signal is sent to the output ends of the second controllable switch and the seventh controllable switch.

11. The scan driving circuit of claim 7, wherein the second pull-down maintaining unit further comprises a fourteenth controllable switch, a control end of the fourteenth controllable switch is coupled to the control ends of the eighth and ninth controllable switches, an input end of the fourteenth controllable switch is coupled to the output end of the nineteenth controllable switch, and the reference low-level signal is sent to an output end of the fourteenth controllable switch;

when the current scanning line is inactive and the second pull-down maintaining unit turns on, the fourteenth controllable switch turns on, and the reference low-level signal is sent to the output end of the nineteenth controllable switch;

when the current scanning line is active, the second pull-down maintaining unit turns off, and the fourteenth controllable switch turns off, and the reference low-level signal is not sent to the output end of the nineteenth controllable switch.

12. The scan driving circuit of claim 7, wherein the pull-down maintaining assembly further comprises a diverter switch, a control end of the diverter switch is coupled to the output end of the pull-up control assembly, and the diverter switch is arranged between the control ends of the first and second controllable switches and the control ends of the eighth and ninth controllable switches;

when the current scanning line is active, the diverter switch turns on, and the first pull-down maintaining unit is connected to the second pull-down maintaining unit, and electric potential of one of the control ends of the first and second pull-down maintaining units, that is at high level, is reduced by electric potential of another control end that is at low level, and the first and second pull-down maintaining units turn off.

13. The scan driving circuit of claim 1, wherein the pull-up control assembly comprises a seventeenth controllable switch;

an output end of the seventeenth controllable switch is coupled to a control end of the pull-up assembly, a previous down-transmitting signal is sent to a control end of the seventeenth controllable switch, and a previous scanning line or the previous down-transmitting signal is sent to an input end of the seventeenth controllable switch;

the pull-up assembly comprises an eighteenth controllable switch;

a control end of the eighteenth controllable switch is coupled to the output end of the pull-up control assembly, a clock scanning signal is sent to an input end of the eighteenth controllable switch, and an output end of the eighteenth controllable switch is coupled to the current scanning line;

the scan driving circuit further comprises a pull-down assembly, and the pull-down assembly comprises a twentieth controllable switch and a twenty-first controllable switch;

control ends of the twentieth controllable switch and the twenty-first controllable switch are coupled to a next scanning line, an input end of the twentieth controllable switch is coupled to the current scanning line, and the reference low-level signal is sent to an output end of the twentieth controllable switch;

an input end of the twenty-first controllable switch is coupled to the output end of the pull-up control assembly, and the reference low-level signal is sent to an output end of the twenty-first controllable switch;

the scan driving circuit further comprises a storage capacitor, a first end of the storage capacitor is coupled to the output end of the pull-up control assembly, and a second end of the storage capacitor is coupled to the output end of the pull-up assembly and the pull-down maintaining assembly.

14. The scan driving circuit of claim 2, wherein the pull-up control assembly comprises a seventeenth controllable switch;

an output end of the seventeenth controllable switch is coupled to a control end of the pull-up assembly, a previous down-transmitting signal is sent to a control end of the seventeenth controllable switch, and a previous scanning line or the previous down-transmitting signal is sent to an input end of the seventeenth controllable switch;

the pull-up assembly comprises an eighteenth controllable switch;

a control end of the eighteenth controllable switch is coupled to the output end of the pull-up control assembly, a clock scanning signal is sent to an input end of the eighteenth controllable switch, and an output end of the eighteenth controllable switch is coupled to the current scanning line;

the scan driving circuit further comprises a pull-down assembly, and the pull-down assembly comprises a twentieth controllable switch and a twenty-first controllable switch;

control ends of the twentieth controllable switch and the twenty-first controllable switch are coupled to a next scanning line, an input end of the twentieth controllable switch is coupled to the current scanning line, and the reference low-level signal is sent to an output end of the twentieth controllable switch;

an input end of the twenty-first controllable switch is coupled to the output end of the pull-up control assembly, and the reference low-level signal is sent to an output end of the twenty-first controllable switch;

the scan driving circuit further comprises a storage capacitor, a first end of the storage capacitor is coupled to the output end of the pull-up control assembly, and a second end of the storage capacitor is coupled to the output end of the pull-up assembly and the pull-down maintaining assembly.

15. The scan driving circuit of claim 3, wherein the pull-up control assembly comprises a seventeenth controllable switch;

an output end of the seventeenth controllable switch is coupled to a control end of the pull-up assembly, a previous down-transmitting signal is sent to a control end of the seventeenth controllable switch, and a previous scanning line or the previous down-transmitting signal is sent to an input end of the seventeenth controllable switch;

the pull-up assembly comprises an eighteenth controllable switch;

a control end of the eighteenth controllable switch is coupled to the output end of the pull-up control assembly, the clock scanning signal is sent to an input end of the eighteenth controllable switch, and an output end of the eighteenth controllable switch is coupled to the current scanning line;

the scan driving circuit further comprises a pull-down assembly, and the pull-down assembly comprises a twentieth controllable switch and a twenty-first controllable switch;

control ends of the twentieth controllable switch and the twenty-first controllable switch are coupled to a next scanning line, an input end of the twentieth controllable switch is coupled to the current scanning line, and the reference low-level signal is sent to an output end of the twentieth controllable switch;

an input end of the twenty-first controllable switch is coupled to the output end of the pull-up control assembly, and the reference low-level signal is sent to an output end of the twenty-first controllable switch;

the scan driving circuit further comprises a storage capacitor, a first end of the storage capacitor is coupled to the output end of the pull-up control assembly, and a second end of the storage capacitor is coupled to the output end of the pull-up assembly and the pull-down maintaining assembly.

16. The scan driving circuit of claim 7, wherein the pull-up control assembly comprises a seventeenth controllable switch;

an output end of the seventeenth controllable switch is coupled to a control end of the pull-up assembly, a previous down-transmitting signal is sent to a control end of the seventeenth controllable switch, and a previous scanning line or the previous down-transmitting signal is sent to an input end of the seventeenth controllable switch;

the pull-up assembly comprises an eighteenth controllable switch;

a control end of the eighteenth controllable switch is coupled to the output end of the pull-up control assembly, the clock scanning signal is sent to an input end of the eighteenth controllable switch, and an output end of the eighteenth controllable switch is coupled to the current scanning line;

the scan driving circuit further comprises a pull-down assembly, and the pull-down assembly comprises a twentieth controllable switch and a twenty-first controllable switch;

control ends of the twentieth controllable switch and the twenty-first controllable switch are coupled to a next scanning line, an input end of the twentieth controllable switch is coupled to the current scanning line, and the reference low-level signal is sent to an output end of the twentieth controllable switch;

an input end of the twenty-first controllable switch is coupled to the output end of the pull-up control assembly, and the reference low-level signal is sent to an output end of the twenty-first controllable switch;

the scan driving circuit further comprises a storage capacitor, a first end of the storage capacitor is coupled to the output end of the pull-up control assembly, and a second end of the storage capacitor is coupled to the output end of the pull-up assembly and the pull-down maintaining assembly.

17. A liquid crystal display device (LCD), comprising:

a scan driving circuit

wherein the scan driving circuit comprises a pull-up assembly, a pull-up control assembly that drives the pull-up assembly, a pull-down maintaining assembly, a reference low-level signal, a pull-down maintaining signal, and a down-transmitting assembly;

an output end of the pull-up assembly is coupled to a current scanning line, and the reference low-level signal is sent to the output end of the pull-up control assembly and the current scanning line via the pull-down maintaining assembly;

the pull-down maintaining signal is sent to a control end of the pull-down maintaining assembly;

a control end of the down-transmitting assembly is coupled to the output end of the pull-up control assembly and a control end of the pull-up assembly, and a current down-transmitting signal is output from an output end of the down-transmitting assembly.

18. The LCD of claim 17, wherein the pull-down maintaining assembly comprises a first pull-down maintaining assembly and a second pull-down maintaining assembly;

input ends of the first pull-down maintaining assembly and the second pull-down maintaining assembly are coupled to the output end of the pull-up control assembly, the pull-down maintaining signal is sent to control ends of the first pull-down maintaining assembly and the second pull-down maintaining assembly, and the reference low-level signal is sent to output ends of the first pull-down maintaining assembly and the second pull-down maintaining assembly;

the scan driving circuit further comprises a diverter switch connected between the control ends of the first pull-down maintaining assembly and the second pull-down maintaining assembly, and a control end of the diverter switch is coupled to the output end of the pull-up control assembly;

when the current scanning line is active, the diverter switch turns off the first pull-down maintaining assembly and the second pull-down maintaining assembly, and the reference low-level signal is not sent to the output end of the pull-up control assembly and the current scanning line.

19. The LCD of claim 17, wherein the pull-down maintaining assembly comprises the first pull-down maintaining assembly comprising a first pull-down maintaining unit and a first pull-down maintaining control unit, the first pull-down maintaining control unit drives the first pull-down maintaining unit;

the first pull-down maintaining unit comprises a first controllable switch and a second controllable switch;

the pull-down maintaining signal comprises a first pull-down maintaining signal, and the first pull-down maintaining signal is sent to control ends of the first controllable switch and the second controllable switch via the first pull-down maintaining control unit;

the reference low-level signal is sent to the current scanning line via the first controllable switch, and is sent to the output end of the pull-up control assembly via the second controllable switch;

the down-transmitting assembly comprises a nineteenth controllable switch, a control end of the nineteenth controllable switch is coupled to the output end of the pull-up control assembly and the control end of the pull-up assembly, a clock scanning signal is sent to an input end of the nineteenth controllable switch, and the current down-transmitting signal is output from an output end of the nineteenth controllable switch;

the first pull-down maintaining unit further comprises a seventh controllable switch;

a control end of the seventh controllable switch is coupled to the control ends of the first and second controllable switches, an input end of the seventh controllable switch is coupled to the output end of the nineteenth controllable switch, and the reference low-level signal is sent to an output end of the seventh controllable switch;

when the current scanning line is inactive, the first pull-down maintaining control unit controls the first controllable switch, the second controllable switch, and the seventh controllable switch to turn on according to the first pull-down maintaining signal, and the first controllable switch controls the reference low-level signal to be sent to the current scanning line, the second controllable switch controls the reference low-level signal to be sent to the output end of the pull-up control assembly, and the seventh controllable switch controls the reference low-level signal to be sent to the output end of the nineteenth controllable switch;

when the current scanning line is active, the first pull-down maintaining control unit controls the first controllable switch and the second controllable switch to turn off according to the first pull-down maintaining signal;

the first controllable switch controls the reference low-level signal to be not sent to the current scanning line, the second controllable switch controls the reference low-level signal to be not sent to the output end of the pull-up control assembly, and the seventh controllable switch controls the reference low-level signal to be not sent to the output end of the nineteenth controllable switch;

the first pull-down maintaining control unit comprises a third controllable switch, a fourth controllable switch, and a fifth controllable switch;

the pull-down maintaining signal further comprises a second pull-down maintaining signal, and logical operation of the second pull-down maintaining signal is opposite to logical operation of the first pull-down maintaining signal;

the third controllable switch uses diode connection method, the first pull-down maintaining signal is sent to an input end and a control end of the third controllable switch;

an output end of the third controllable switch is coupled to a control end of the fourth controllable switch;

the first pull-down maintaining signal is sent to an input end of the fourth controllable switch, and an output end of the fourth controllable switch is coupled to the control ends of the first and second controllable switches;

the second pull-down maintaining signal is sent to a control end of the fifth controllable switch, the first pull-down maintaining signal is sent to an input end of the fifth controllable switch, and an output end of the fifth controllable switch is coupled to the control ends of the first and second controllable switches;

the pull-down maintaining assembly further comprises a turn-off unit, and the turn-off unit comprises a sixth controllable switch;

a control end of the sixth controllable switch is coupled to the output end of the pull-up control assembly, an input end of the sixth controllable switch is coupled to the control end of the fourth controllable switch, and the reference low-level signal or the second pull-down maintaining signal is sent to an output end of the sixth controllable switch.

20. The LCD of claim 19, wherein the pull-down maintaining assembly further comprises a second pull-down maintaining assembly comprising a second pull-down maintaining unit and a second pull-down maintaining control unit, the second pull-down maintaining control unit drives the second pull-down maintaining unit;

the pull-down maintaining signal comprises a second pull-down maintaining signal, logical operation of the second pull-down maintaining signal is opposite to logical operation of the first pull-down maintaining signal;

the second pull-down maintaining unit comprises an eighth controllable switch and a ninth controllable switch;

the second pull-down maintaining signal is sent to control ends of the eighth and ninth controllable switches via the second pull-down maintaining control unit;

the reference low-level signal is sent to the current scanning line via the eighth controllable switch, and is sent to the output end of the pull-up control assembly via the ninth controllable switch;

when the current scanning line is inactive, the first pull-down maintaining unit and the second pull-down maintaining unit alternately turn on;

when the second pull-down maintaining unit turn on, the eighth and ninth controllable switches turn on, and the reference low-level signal is sent to the output end of the pull-up control assembly and the current scanning line;

when the current scanning line is active, the first pull-down maintaining unit and the second pull-down maintaining unit turn off, and the first, second, eighth, and ninth controllable switches turn off, and the reference low-level signal is not sent to the output end of the pull-up control assembly and the current scanning line;

the second pull-down maintaining control unit comprises a tenth controllable switch, an eleventh controllable switch, and a twelfth controllable switch;

the tenth controllable switch uses diode connection method, the second pull-down maintaining signal is sent to an input end and a control end of the tenth controllable switch;

an output end of the tenth controllable switch is coupled to a control end of the eleventh controllable switch;

the second pull-down maintaining signals is sent to an input end of the eleventh controllable switch, and an output end of the eleventh controllable switch is coupled to the control ends of the eighth and ninth controllable switches;

the first pull-down maintaining signal is sent to a control end of the twelfth controllable switch, the second pull-down maintaining signal is sent to an input end of the twelfth controllable switch, and an output end of the twelfth controllable switch is coupled to the control ends of the eighth and ninth controllable switches;

when the current scanning line is inactive and the second pull-down maintaining assembly turns on, the tenth, eleventh, and twelfth controllable switches control the eighth and ninth controllable switches to turn on according to the first and second pull-down maintaining signals, and the reference low-level signal is sent to the output end of the pull-up control assembly and the current scanning line;

the reference low-level signal comprises a first reference low-level signal and a second reference low-level signal;

electric potential of the second reference low-level signal is less than electric potential of the first reference low-level signal, and electric potential of the pull-down maintaining signal at low level is less than electric potential of the second reference low-level signal;

the first reference low-level signal is sent to the current scanning line via the eighth controllable switch, and the second reference low-level signal is sent to the output end of the pull-up control assembly via the ninth controllable switch;

when the current scanning line is inactive and the second pull-down maintaining assembly turns on, the eighth controllable switch and the ninth controllable switch turn on, and the eighth controllable switch controls the first reference low-level signal to be sent to the current scanning line, the ninth controllable switch controls the second reference low-level signal to be sent to the output end of the pull-up control assembly;

the pull-down maintaining assembly further comprises the turn-off unit, and the turn-off unit comprises a thirteenth controllable switch;

the reference low-level signal comprises a first reference low-level signal and a second reference low-level signal;

electric potential of the second reference low-level signal is less than electric potential of the first reference low-level signal, and electric potential of the pull-down maintaining signal at low level is less than electric potential of the second reference low-level signal;

the first reference low-level signal is sent to the current scanning line via the eighth controllable switch, and the second reference low-level signal is sent to the output end of the pull-up control assembly via the ninth controllable switch;

an input end of the thirteenth controllable switch is coupled to the control ends of the eighth controllable switch and the ninth controllable switch, the first reference low-level signal, the second reference low-level signal, or the second pull-down maintaining signal is sent to an output end of the thirteenth controllable switch;

the first reference low-level signal is sent to the output end of the first controllable switch, and the second reference low-level signal is sent to the output ends of the second controllable switch and the seventh controllable switch;

the second pull-down maintaining unit further comprises a fourteenth controllable switch;

a control end of the fourteenth controllable switch is coupled to the control ends of the eighth and ninth controllable switches, an input end of the fourteenth controllable switch is coupled to the output end of the nineteenth controllable switch, and the reference low-level signal is sent to an output end of the fourteenth controllable switch;

when the current scanning line is inactive and the second pull-down maintaining unit turns on, the fourteenth controllable switch turns on, and the reference low-level signal is sent to the output end of the nineteenth controllable switch;

when the current scanning line is active, the second pull-down maintaining unit turns off, and the fourteenth controllable switch turns off, and the reference low-level signal is not sent to the output end of the nineteenth controllable switch;

the pull-down maintaining assembly further comprises a diverter switch, a control end of the diverter switch is coupled to the output end of the pull-up control assembly, and the diverter switch is arranged between the control ends of the first and second controllable switches and the control ends of the eighth and ninth controllable switches;

when the current scanning line is active, the diverter switch turns on, and the first pull-down maintaining unit is connected to the second pull-down maintaining unit, and electric potential of one of the control ends of the first and second pull-down maintaining units, that is at high level, is reduced by electric potential of another control end that is at low level, thus, the first and second pull-down maintaining units turn off;

the pull-up control assembly comprises a seventeenth controllable switch;

an output end of the seventeenth controllable switch is coupled to a control end of the pull-up assembly, a previous down-transmitting signal is sent to a control end of the seventeenth controllable switch, and a previous scanning line or the previous down-transmitting signal is sent to an input end of the seventeenth controllable switch;

the pull-up assembly comprises an eighteenth controllable switch;

a control end of the eighteenth controllable switch is coupled to the output end of the pull-up control assembly, a clock scanning signal is sent to an input end of the eighteenth controllable switch, and an output end of the eighteenth controllable switch is coupled to the current scanning line;

the scan driving circuit further comprises a pull-down assembly, and the pull-down assembly comprises a twentieth controllable switch and a twenty-first controllable switch;

control ends of the twentieth controllable switch and the twenty-first controllable switch are coupled to a next scanning line, an input end of the twentieth controllable switch is coupled to the current scanning line, and the reference low-level signal is sent to an output end of the twentieth controllable switch;

an input end of the twenty-first controllable switch is coupled to the output end of the pull-up control assembly, and the reference low-level signal is sent to an output end of the twenty-first controllable switch;

the scan driving circuit further comprises a storage capacitor, a first end of the storage capacitor is coupled to the output end of the pull-up control assembly, and a second end of the storage capacitor is coupled to the output end of the pull-up assembly and the pull-down maintaining assembly.