Shift register with two-way transmission and liquid crystal display device using same

Abstract

A shift register includes individually connected shift register units. Each shift register unit includes a switching unit, a pre-charging unit, a pulse signal output unit, a low level voltage signal control unit, a first clock pulse signal input, a second clock pulse signal input, and an output. The first and the second clock pulse signal inputs respectively receive a first clock signal and a second clock signal, the first clock signal and the second clock signal having reverse clock pulses during each clock cycle. The switching unit receives at least one external starting signal and a high level signal, when the at least one external starting signal is high level, the switching unit is turned on and outputs the high level signal to the pre-charging unit. When the second clock signal is high level, the pre-charging unit receives the high level signal and charges, and when the first clock signal is high level, the pre-charging unit discharges. The pulse signal output unit receives the first clock signal and outputs the first clock signal to the output after the pre-charging unit charges and before the pre-charging unit finishes discharging. The low level voltage signal control unit receives the first clock signal and the second clock signal, after the pre-charging unit finishes discharging, the low level voltage signal control unit pulls down a voltage level on the output at low level when the second clock signal are high level.