Scanning signal line drive circuit and display device having the same

摘要

Stability of a circuit operation in a monolithic gate driver is improved. A bistable circuit is provided with a charge replenishment circuit (71) including: a capacitor (CAP2); a thin-film transistor (MA) having a first electrode supplied with a first clock for charge replenishment (CKA), a second electrode connected to a third-node (N3) connected to one end of the capacitor (CAP2), and a third electrode connected to a second-node (N2) to be maintained at the high level during a normal operation period; and a thin-film transistor (MB) having a first electrode supplied with a second clock for charge replenishment (CKB), a second electrode supplied with a high-level DC power supply potential (VDD), and a third electrode connected to the third-node (N3). The first clock for charge replenishment (CKA) and the second clock for charge replenishment (CKB) are alternately driven to the high level so as to eliminate a period in which “the first clock for charge replenishment (CKA) is at the high level and the second clock for charge replenishment (CKB) is at the high level”.

主权项

1. A scanning signal line drive circuit of a display device, that drives a plurality of scanning signal lines which are arrayed in a display unit, the circuit comprising:
a shift register having a plurality of bistable circuits connected in series with each other, outputted signals from the plurality of bistable circuits being sequentially driven active based on a plurality of clock signals that are externally inputted and cyclically repeat a first level and a second level, wherein each bistable circuit includes:
a first-input-node configured to receive an outputted signal from a bistable circuit of a stage before the each bistable circuit as a set signal;a first-output-node connected to the scanning signal line and configured to output an outputted signal from the each bistable circuit as a scanning signal for driving the scanning signal line;a first output control switching element having a second electrode supplied with one of the plurality of clock signals as a first clock for operation control and a third electrode connected to the first-output-node;a first-node turnon switching element configured to change a level of a first-node to an ON level based on the set signal, the first-node being connected to a first electrode of the first output control switching element;at least one of a first first-node turnoff switching element and a first first-output-node turnoff switching element, the first first-node turnoff switching element having a second electrode connected to the first-node and being configured to change the level of the first-node to an OFF level, the first first-output-node turnoff switching element having a second electrode connected to the first-output-node, having a third electrode supplied with an OFF level potential, and being configured to change a level of the first-output-node to the OFF level;a second-node turnoff switching element having a second electrode connected to a second-node, having a third electrode supplied with an OFF level potential, and configured to turn the second-node to the OFF level during a period in which the first-node is to be maintained at the ON level, the second-node being connected to a first electrode of at least one of the first first-node turnoff switching element and the first first-output-node turnoff switching element;a first charge replenishment switching element having a first electrode supplied with one of the plurality of clock signals as a first clock for charge replenishment and having a third electrode connected to the second-node;a capacitative element having one end connected to a third-node connected to a second electrode of the first charge replenishment switching element; anda second charge replenishment switching element having a third electrode connected to the third-node, having a first electrode supplied with one of the plurality of clock signals as a second clock for charge replenishment, and configured to charge the capacitative element based on the second clock for charge replenishment, the first charge replenishment switching element is turned to an ON state when the first clock for charge replenishment is at the first level, the second charge replenishment switching element is turned to an ON state when the second clock for charge replenishment is at the first level, and when the first clock for charge replenishment is at the first level, the second clock for charge replenishment is at the second level.