Shift register
A shift register comprises a plurality of stages, {S n }, n=1, 2, . . . , N, N being a positive integer. In one embodiment, each stage S n includes a pull-up circuit having an input for receiving one of a first clock signal, CK 1 , and a second clock signal, XCK 1 , an output for responsively outputting an output signal, O n , and an input node Q n , a pull-up control circuit electrically coupled to the input node Q n and configured such that when receiving a first input signal, the pull-up control circuit responsively generates a signal that is provided to the input node Q n to turn on the pull-up circuit, a pull-down circuit electrically coupled to the input node Q n and configured to provide a first voltage to one of the input node Q n and the output of the pull-up circuit, and a pull-down control circuit configured to receive one of a third clock signal, CK 2 , and a fourth clock signal, XCK 2 , and responsively generate the first voltage to turn on the pull-down circuit of the stage S n and the pull-down circuit of one of the stage S n−1 and the stage S n+1 .
1. A shift register, comprising a plurality of stages, {S n }, n=1, 2, . . . , N, N being a positive integer, wherein each stage S n comprises:
(a) a pull-up circuit having an input for receiving a corresponding clock signal Cn, an output for responsively outputting an output signal, O n , and an input node, Q n , between the input and the output;
(b) a pull-up control circuit electrically coupled to the input node Q n of the pull-up circuit and configured such that when receiving a first input signal, the pull-up control circuit responsively generates a signal that is identical to the first input signal and is provided to the input node Q n of the pull-up circuit to turn on the pull-up circuit;
(c) a first pull-down circuit electrically coupled to the input node Q n and the output of the pull-up circuit and configured to receive a pull-down signal K n ;
(d) a second pull-down circuit electrically coupled to the input node Q n and the output of the pull-up circuit, and configured to receive a second input signal;
(e) a third pull-down circuit electrically coupled to the input node Q n and the output of the pull-up circuit and configured to receive a third input signal; and
(f) a first pull-down control circuit configured to receive a fourth input signal and responsively generate the pull-down signal K n that is provided to the first pull-down circuit of the stage S n and the second pull-down circuit of one of the stage S n−1 and the stage S n+1 , respectively.
2. The shift register of claim 1 , wherein each of the clock signals {Cn}, n=1, 2, 3, . . . , N, is characterized with a frequency and a phase, wherein the frequencies of the clock signals {Cn} are substantially identical, and the phases of the clock signals {Cn} are sequentially shifted, respectively.
3. The shift register of claim 2 , wherein the fourth input signal is corresponding to a first supply voltage signal, VDDa, when n is an odd integer, or a second supply voltage signal, VDDb, when n is an even integer, wherein each of the first supply voltage signal VDDa and the second supply voltage signal VDDb is characterized with a frequency and a phase, wherein the frequencies of the first supply voltage signal VDDa and the second supply voltage signal VDDb are substantially identical, and the phases of the first supply voltage signal VDDa and the second supply voltage signal VDDb are substantially reversed, respectively.
4. The shift register of claim 3 , wherein the second input signal is corresponding to the pull-down signal K n−1 of the stage S n−1 or the pull-down signal K n+1 of the stage S n+1 , wherein the third input signal is corresponding to the output signal O n+2 of the stage S n+2 .
5. The shift register of claim 3 , wherein the first input signal is corresponding to the output signal O n−1 of the stage S n−1 for n=2, 3, 4, . . . , N, or a start signal for n=1.
6. The shift register of claim 3 , wherein the first input signal is corresponding to the output signal O n−2 of the stage S n−2 for n=3, 4, 5, . . . , N, or a start signal for n=1 and 2.
7. The shift register of claim 3 , wherein the first input signal is corresponding to a start signal.