Shift cache circuit

Abstract

The invention discloses a shift cache circuit. The shift cache circuit comprises a plurality of shift cache layer for providing a plurality of grid signals to a plurality of grid lines. Each layer of shift cache comprises a pull-up unit, an input unit for receiving an input signal, an energy storage unit for providing a drive control voltage according to the input signal, a discharge unit, a coupling unit and a pull-down unit. The pull-up unit pulls up a first grid signal according to the drive control voltage; the discharge unit is used for executing discharge action so as to pull down the drive control voltage; the coupling unit is used for coupling the energy storage unit with a post-layer shift cache so as to cause a second grid signal generated by the post-layer shift cache to drop with pull-down drive control voltage; and the pull-down unit pulls down the first grid signal according to the second grid signal.

Description

technical field [0001] The invention relates to a shift register circuit, in particular to a shift register circuit capable of reducing leakage current and voltage stress. Background technique [0002] A liquid crystal display (Liquid Crystal Display; LCD) is a flat panel display widely used at present, which has the advantages of light and thin appearance, power saving and no radiation. The working principle of the liquid crystal display device is to change the arrangement state of the liquid crystal molecules in the liquid crystal layer by changing the voltage difference between the two ends of the liquid crystal layer, so as to change the light transmittance of the liquid crystal layer, and cooperate with the light source provided by the backlight module to display images. Generally speaking, a liquid crystal display device includes a plurality of pixel units, a shift register circuit and a source driver. The source driver is used to provide multiple data signals to mult...

AI Technical Summary

Problems solved by technology

like figure 2 As shown, when the driving control voltage VQn is not pulled up to the first high voltage Vh1 or the second high voltage Vh2, the rising edge and falling edge of the first clock pulse CK1 can be caused by the capacitive coupling effect of the element of the pull-up unit 120 The ripple (Ripple) of the driving control voltage VQn, and because this ripple is an AC signal that periodically swings between the peak voltage Vrc1 and the valley voltage Vrt1 based on the low power supply voltage Vss, the peak voltage Vrc1 may be caused by component aging, Temperature changes or other operating factors increase the voltage to close to zero, which will cause the leakage current of the pull-up unit 120, and then cause the voltage potential of the gate signal SGn to drift significantly and reduce the image display quality.

On the other hand, when the driving control voltage VQn is not pulled up to the first high voltage Vh1 or the second high voltage Vh2, the pull-down control voltage Vdn is kept approximately at the high power supply voltage Vdd for continuously turning on the discharge unit 140 The transistors of the pull-down unit 150 are used to continuously pull down the driving control voltage VQn and the gate signal SGn, that is, the transistors of the discharge unit 140 and the pull-down unit 150 are subjected to high voltage stress for a long time, so it is easy to cause the threshold voltage to drift, thereby reducing the shift. Reliability and Service Life of the Register Circuit 100

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