Patent ID: 9576677
Date: 2017-02-21
CPC Classifications: G09G,G11C

Claim:
1. A scan driving circuit, executing a driving operation for cascaded scan lines, comprising: a pull-up control module receiving a previous-level down-stream signal, and generating a scan level signal corresponding to one of the scan lines according to the previous-level down-stream signal; a pull-up module pulling up a scan signal of the corresponding scan line according to the scan level signal and a present-level clock signal; a pull-down module pulling down a scan signal of the corresponding scan line according to a next-two-level clock signal and a next-two-level scan signal; a pull-down maintaining module keeping the scan signal of the corresponding scan line in a low-level, and comprising a first pull-down maintaining unit and a second pull-down maintaining unit, wherein the first pull-down maintaining unit and the second pull-down maintaining unit work alternately; a down-stream module transmitting a present-level down-stream signal to a next-level pull-up control module; and a bootstrap capacitor generating a high-level of the scan signal of the scan line; wherein when the pull-up control module generates a scan level signal, the pull-up control module and the pull-down maintaining module use a constant high-level voltage to avoid an electrical leakage phenomenon; and the pull down module uses a present-level scan signal to avoid the electrical leakage phenomenon; wherein the pull-up control module comprises a first switch transistor, a control end of the first switch transistor inputs the previous-level down-stream signal, an input end of the first switch transistor inputs the constant high-level voltage, and an output end of the first switch transistor is connected to the pull-up module, the pull-down module, the pull-down maintaining module, the down-stream module and the bootstrap capacitor.