US 7,688,934 B2 · Shift register and shift register unit for diminishing clock coupling effect

Abstract

A shift register and a shift register unit for diminishing clock coupling effect are introduced herein. Each stage shift register unit includes at least one pull-up driving module, a pull-up module, at least one pull-down module and a pull-down driving module. Before a waveform of either a first clock signal or a second clock signal employed by the pull-up module transits into a rising edge, the pull-down driving module employs a first periodic signal to turn on the pull-down module in advance for a specific period, and/or before the waveform of the first or second clock signal employed by the pull-up module transits into a falling edge, the pull-down driving module employs a second periodic signal to turn off the pull-down module in advance for a specific period. Accordingly, the pull-down module can gain a sufficient capability against the clock coupling effect so as to optimize the waveform outputted from the shift register unit.

Claims30

Dependent claims

A shift register comprising multi-stage shift register units each of which comprises:

at least one pull-up driving module for providing a driving signal according to a pulse signal;
a pull-up module outputting an output signal according to one of a first signal and a second signal when the pull-up module is triggered by the driving signal to be electrically conductive;
at least one pull-down module for providing the pull-up module with a first source voltage;
and
at least one pull-down driving module based on one of a third signal and a fourth signal, triggering the at least one pull-down module for a specific period before a waveform of either the first signal or the second signal transits into either a rising edge or a falling edge.

2 more elements

A shift register comprising multi-stage shift register units each of which comprises:

a pull-up module outputting an output signal according to one of a first signal and a second signal;
at least one pull-up driving module turning on the pull-up module in response to either an output signal generated from a previous stage shift register unit or an initial signal, and turning off the pull-up module in response to an output signal generated from a next stage shift register unit;
at least one pull-down module for providing the pull-up module with a first source voltage to pull down a level of the output signal of said pull-up module;
and
at least one pull-down driving module based on a third signal to turn on the at least one pull-down module for a specific period before a waveform of either the first signal or the second signal transits into a rising edge, and based on a fourth signal to turn off the at least one pull-down module for a specific period before the waveform of either the first signal or the second signal transits into a falling edge.

2 more elements

Dependencies are inferred from the claim text.

Shift register and shift register unit for diminishing clock coupling effect

Life of this patent

Shift register and shift register unit for diminishing clock coupling effect

Life of this patent

Abstract

Claims30