# US 9,437,152 B2 · Scan driving circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,437,152 B2 - Document ID: US9437152B2 - Status: Granted - Kind: B2 - Application number: 14/416,282 - Filed: 2014-12-09 - Published: 2016-06-30 - Granted: 2016-09-06 - Earliest claimed: 2014-11-14 - Assignees: Shenzhen China Star Optoelectronics Technology Co., Ltd. - Applicants: Shenzhen China Star Optoelectronics Technology Co., Ltd. - Inventors: Juncheng Xiao - Web page: https://patentgrep.com/patent/US9437152B2 ## CPC - G09G 3/3677: {suitable for active matrices only} - H03K 17/145: {in field-effect transistor switches} - H03K 17/162: {without feedback from the output circuit to the control circuit} - H03K 17/6871: {the output circuit comprising more than one controlled field-effect transistor} - G09G 2300/0408: Integration of the drivers onto the display substrate - G09G 2300/0871: with level shifting - G09G 2310/0202: Addressing of scan or signal lines - G09G 2310/06: Details of flat display driving waveforms - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) ## Abstract A scan driving circuit is provided. The scan driving circuit includes a pull-up control module, a pull-up module, a pull-down module, a pull-down maintenance module, a bootstrap capacitor, and a low-level constant source. The pull-up control module herein is respectively coupled to the pull-up module, the pull-down module, the pull-down maintenance module, and the bootstrap capacitor; the low-level constant source is respectively coupled to the pull-down maintenance module and the pull-down module. The present invention can avoid a leakage phenomenon well and improve reliability of the scan driving circuit. ## Claims ### Claim 1 A scan driving circuit for driving a scan line of cascaded stages, comprising: a pull-up control module utilized to receive a scanning signal of a previous stage, and to generate a scan level signal of the corresponding scan line according to the scanning signal of the previous stage; a pull-up module utilized to lift a scanning signal of a present stage of the corresponding scan line according to the scan level signal and a clock signal of the present stage; a pull-down module utilized to lower the scan level signal of the corresponding scan line according to a scanning signal of a next stage; a pull-down maintenance module utilized to maintain a low level of the scan level signal of the corresponding scan line; a bootstrap capacitor utilized to a high level of the scanning signal of the present stage of the scan line; a reset module utilized to reset the scan level signal of the present stage of the scan line; and a low-level constant source utilized to provide a pull-down low level; wherein the pull-up control module is respectively coupled to the pull-up module, the pull-down module, the pull-down maintenance module, and the bootstrap capacitor; the low-level constant source is respectively coupled to the pull-down maintenance module and the pull-down module; wherein the pull-up control module further comprises a first switch, the scanning signal of the previous stage being input to a control terminal of the first switch, the scanning signal of the previous stage being input to an input terminal the first switch, an output terminal of the first switch respectively coupled to the pull-up module, the pull-down module, the pull-down maintain module, and the bootstrap capacitor. ### Claim 2 (depends on 1) The scan driving circuit according to claim 1, wherein the pull-up module comprises a second switch, a control terminal of the second switch coupled to the output terminal of the first switch of the pull-up control module, the clock signal of the present stage being input to an input terminal of the second switch, an output terminal of the second switch outputting the scanning signal of the present stage. ### Claim 3 (depends on 1) The scan driving circuit according to claim 1, wherein the pull-down module comprises a third switch, the scanning signal of the next stage being input to a control terminal of the third switch, an input terminal of the third switch coupled to the output terminal of the first switch of the pull-up control module, an output terminal of the third switch coupled to the low-level constant source. ### Claim 4 (depends on 1) The scan driving circuit according to claim 1, wherein the pull-down maintenance module comprises a first pull-down maintenance unit, a second pull-down maintenance unit, a thirteenth switch, and a fourteenth switch; a control terminal of the thirteenth switch coupled to the output terminal of the first switch, an output terminal of the thirteenth switch coupled to a reference point K(N), an input terminal of the thirteenth switch coupled to a reference point P(N); the scanning signal of the previous stage being input to a control terminal of the fourteenth switch, an output terminal of the fourteenth switch coupled to the reference point K(N), an input terminal of the fourteenth switch coupled to the reference point P(N); the first pull-down maintenance unit comprising a ninth switch, a tenth switch, a sixth switch, an eighth switch, a sixteenth switch; a control terminal of the tenth switch coupled to the reference point K(N), an input terminal of the tenth switch coupled to the low-level constant source, an output terminal of the tenth switch coupled to the output terminal of the second switch; a control terminal of the ninth switch coupled to the reference point K(N), an input terminal of the ninth switch coupled to the low-level constant source, an output terminal of the ninth switch coupled to the output terminal of the first switch; a control terminal of the sixth switch coupled to a first pulse signal, an input terminal of the sixth switch coupled to the first pulse signal, an output terminal of the sixth switch coupled to the reference point K(N); a control terminal of the sixteenth switch coupled to a second pulse signal, an input terminal of the sixteenth switch coupled to the first pulse signal, an output terminal of the sixteenth switch coupled to the reference point K(N); a control terminal of the eighth switch coupled to the output terminal of the first switch, an input terminal of the eighth switch coupled to the low-level constant source, an output terminal of the eighth switch coupled to the reference point K(N); the second pull-down maintenance unit comprising an eleventh switch, a twelfth switch, a fifth switch, a fifteenth switch, and a seventh switch; a control terminal of the eleventh switch coupled to the reference point P(N), an input terminal of the eleventh switch coupled to the low-level constant source, an output terminal of the eleventh switch coupled to the output terminal of the second switch; a control terminal of the twelfth switch coupled to the reference point P(N), an input terminal of the twelfth switch coupled to the low-level constant source, an output terminal of the twelfth switch coupled to the output terminal of the first switch; a control terminal of the fifth switch coupled to the second pulse signal, an input terminal of the fifth switch coupled to the second pulse signal, an output terminal of the fifth switch coupled to the reference point P(N); a control terminal of the fifteenth switch coupled to the first pulse signal, an input terminal of the fifteenth switch coupled to the second pulse signal, an output terminal of the fifteenth switch coupled to the reference point P(N); a control terminal of the seventh switch coupled to the output terminal of the first switch, an input terminal of the seventh switch coupled to the low-level constant source, an output terminal of the seventh switch coupled to the reference point K(N). ### Claim 5 (depends on 4) The scan driving circuit according to claim 4, wherein an electric potential of the first pulse signal is opposite to that of the second pulse signal. ### Claim 6 (depends on 4) The scan driving circuit according to claim 4, wherein the first pull-down maintain further comprises an eighteenth switch, the scanning signal of the previous stage being input to a control terminal of the eighteenth switch, an input terminal of the eighteenth switch coupled to the low-level constant source, an output terminal of the eighteenth switch coupled to the reference point K(N); the second pull-down maintain further comprises an seventeenth switch, the scanning signal of the previous stage being input to a control terminal of the seventeenth switch, an input terminal of the seventeenth switch coupled to the low-level constant source, an output terminal of the seventeenth switch coupled to the reference point P(N). ### Claim 7 (depends on 4) The scan driving circuit according to claim 4, wherein the first pull-down maintain further comprises an eighteenth switch, the scanning signal of the previous stage being input to a control terminal of the eighteenth switch, an input terminal of the eighteenth switch coupled to the low-level constant source, an output terminal of the eighteenth switch coupled to the first pulse signal; the second pull-down maintain further comprises an seventeenth switch, the scanning signal of the previous stage being input to a control terminal of the seventeenth switch, an input terminal of the seventeenth switch coupled to the low-level constant source, an output terminal of the seventeenth switch coupled to the second pulse signal. ### Claim 8 (depends on 7) The scan driving circuit according to claim 7, wherein the first pull-down maintain further comprises a twentieth switch, a control terminal of the twentieth switch coupled to the reference point K(N), an input terminal of the twentieth switch coupled to the reference point K(N), an output terminal of the twentieth switch coupled to the first pulse signal; the second pull-down maintain further comprises a nineteenth switch, a control terminal of the nineteenth switch coupled to the reference point K(N), an input terminal of the nineteenth switch coupled to the reference point K(N), an output terminal of the nineteenth switch coupled to the second pulse signal. ### Claim 9 (depends on 4) The scan driving circuit according to claim 4, wherein the first pulse signal and the second pulse signal are high-frequency pulse signals or low-frequency potential signals. ### Claim 10 A scan driving circuit for driving a plurality of scan lines of cascaded stages, comprising: a pull-up control module utilized to receive a scanning signal of a previous stage, and to generate a scan level signal of the corresponding scan line according to the scanning signal of the previous stage; a pull-up module utilized to lift a scanning signal of a present stage of the corresponding scan line according to the scan level signal and a clock signal of the present stage; a pull-down module utilized to lower the scan level signal of the corresponding scan line according to a scanning signal of a next stage; a pull-down maintenance module utilized to maintain a low level of the scan level signal of the corresponding scan line; a bootstrap capacitor utilized to a high level of the scanning signal of the present stage of the scan line; and a low-level constant source utilized to provide a pull-down low level; wherein the pull-up control module is respectively coupled to the pull-up module, the pull-down module, the pull-down maintenance module, and the bootstrap capacitor; the low-level constant source is respectively coupled to the pull-down maintenance module and the pull-down module. ### Claim 11 (depends on 10) The scan driving circuit according to claim 10, wherein the pull-up control module further comprises a first switch, the scanning signal of the previous stage being input to a control terminal of the first switch, the scanning signal of the previous stage being input to an input terminal the first switch, an output terminal of the first switch respectively coupled to the pull-up module, the pull-down module, the pull-down maintain module, and the bootstrap capacitor. ### Claim 12 (depends on 11) The scan driving circuit according to claim 11, wherein the pull-up module comprises a second switch, a control terminal of the second switch coupled to the output terminal of the first switch of the pull-up control module, the clock signal of the present stage being input to an input terminal of the second switch, an output terminal of the second switch outputting the scanning signal of the present stage. ### Claim 13 (depends on 11) The scan driving circuit according to claim 11, wherein the pull-down module comprises a third switch, the scanning signal of the next stage being input to a control terminal of the third switch, an input terminal of the third switch coupled to the output terminal of the first switch of the pull-up control module, an output terminal of the third switch coupled to the low-level constant source. ### Claim 14 (depends on 11) The scan driving circuit according to claim 11, wherein the pull-down maintenance module comprises a first pull-down maintenance unit, a second pull-down maintenance unit, a thirteenth switch, and a fourteenth switch; a control terminal of the thirteenth switch coupled to the output terminal of the first switch, an output terminal of the thirteenth switch coupled to a reference point K(N), an input terminal of the thirteenth switch coupled to a reference point P(N); the scanning signal of the previous stage being input to a control terminal of the fourteenth switch, an output terminal of the fourteenth switch coupled to the reference point K(N), an input terminal of the fourteenth switch coupled to the reference point P(N); the first pull-down maintenance unit comprising a ninth switch, a tenth switch, a sixth switch, an eighth switch, a sixteenth switch; a control terminal of the tenth switch coupled to the reference point K(N), an input terminal of the tenth switch coupled to the low-level constant source, an output terminal of the tenth switch coupled to the output terminal of the second switch; a control terminal of the ninth switch coupled to the reference point K(N), an input terminal of the ninth switch coupled to the low-level constant source, an output terminal of the ninth switch coupled to the output terminal of the first switch; a control terminal of the sixth switch coupled to a first pulse signal, an input terminal of the sixth switch coupled to the first pulse signal, an output terminal of the sixth switch coupled to the reference point K(N); a control terminal of the sixteenth switch coupled to a second pulse signal, an input terminal of the sixteenth switch coupled to the first pulse signal, an output terminal of the sixteenth switch coupled to the reference point K(N); a control terminal of the eighth switch coupled to the output terminal of the first switch, an input terminal of the eighth switch coupled to the low-level constant source, an output terminal of the eighth switch coupled to the reference point K(N); the second pull-down maintenance unit comprising an eleventh switch, a twelfth switch, a fifth switch, a fifteenth switch, and a seventh switch; a control terminal of the eleventh switch coupled to the reference point P(N), an input terminal of the eleventh switch coupled to the low-level constant source, an output terminal of the eleventh switch coupled to the output terminal of the second switch; a control terminal of the twelfth switch coupled to the reference point P(N), an input terminal of the twelfth switch coupled to the low-level constant source, an output terminal of the twelfth switch coupled to the output terminal of the first switch; a control terminal of the fifth switch coupled to the second pulse signal, an input terminal of the fifth switch coupled to the second pulse signal, an output terminal of the fifth switch coupled to the reference point P(N); a control terminal of the fifteenth switch coupled to the first pulse signal, an input terminal of the fifteenth switch coupled to the second pulse signal, an output terminal of the fifteenth switch coupled to the reference point P(N); a control terminal of the seventh switch coupled to the output terminal of the first switch, an input terminal of the seventh switch coupled to the low-level constant source, an output terminal of the seventh switch coupled to the reference point K(N). ### Claim 15 (depends on 14) The scan driving circuit according to claim 14, wherein an electric potential of the first pulse signal is opposite to that of the second pulse signal. ### Claim 16 (depends on 14) The scan driving circuit according to claim 14, wherein the first pull-down maintain further comprises an eighteenth switch, the scanning signal of the previous stage being input to a control terminal of the eighteenth switch, an input terminal of the eighteenth switch coupled to the low-level constant source, an output terminal of the eighteenth switch coupled to the reference point K(N); the second pull-down maintain further comprises an seventeenth switch, the scanning signal of the previous stage being input to a control terminal of the seventeenth switch, an input terminal of the seventeenth switch coupled to the low-level constant source, an output terminal of the seventeenth switch coupled to the reference point P(N). ### Claim 17 (depends on 14) The scan driving circuit according to claim 14, wherein the first pull-down maintain further comprises an eighteenth switch, the scanning signal of the previous stage being input to a control terminal of the eighteenth switch, an input terminal of the eighteenth switch coupled to the low-level constant source, an output terminal of the eighteenth switch coupled to the first pulse signal; the second pull-down maintain further comprises an seventeenth switch, the scanning signal of the previous stage being input to a control terminal of the seventeenth switch, an input terminal of the seventeenth switch coupled to the low-level constant source, an output terminal of the seventeenth switch coupled to the second pulse signal. ### Claim 18 (depends on 17) The scan driving circuit according to claim 17, wherein the first pull-down maintain further comprises a twentieth switch, a control terminal of the twentieth switch coupled to the reference point K(N), an input terminal of the twentieth switch coupled to the reference point K(N), an output terminal of the twentieth switch coupled to the first pulse signal; the second pull-down maintain further comprises a nineteenth switch, a control terminal of the nineteenth switch coupled to the reference point K(N), an input terminal of the nineteenth switch coupled to the reference point K(N), an output terminal of the nineteenth switch coupled to the second pulse signal. ### Claim 19 (depends on 14) The scan driving circuit according to claim 14, wherein the first pulse signal and the second pulse signal are high-frequency pulse signals or low-frequency potential signals. ### Claim 20 (depends on 10) The scan driving circuit according to claim 10, wherein the scan driving circuit further comprises: a reset module utilized to reset the scan level signal of the present stage of the scan line.