GOA Circuit Pull-Down Holding Sub-Circuit Threshold Deflection
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Solution Overview
Problem
The existing Gate Driver On Array (GOA) circuit suffers from forward deflection of voltage threshold in the pull-down holding sub-circuit, leading to circuit failure due to prolonged high potential status of TFTs, which reduces the reliability and stability of the GOA circuit.
Innovation Solution
The GOA circuit incorporates a pull-down holding circuit with two alternative sub-circuits, where the first and second pull-down holding sub-circuits are connected to first and second reverse clock signals with different potentials, respectively, to mitigate the stress effect on TFTs, thereby correcting the forward deflection issue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If two pull-down holding circuits work alternatively with reverse signals LC1 and LC2, then the circuit can maintain operation for extended periods, but the threshold voltage of TFTs undergoes forward deflection leading to circuit failure
Solution Approach 1:
The patent applies inversion by reversing the clock signal polarity for one of the pull-down holding circuits. Specifically, when the first pull-down holding circuit uses clock signal LC1, the second circuit uses reverse clock signal LC2' (inverted phase of LC2). This inverted signal configuration ensures that when one circuit is active, the other is in a state that counteracts threshold voltage forward deflection, thereby preventing cumulative damage while maintaining continuous operation.
Solution Approach 2:
The patent changes the temporal parameter of the clock signals by introducing phase inversion. The reverse clock signal LC2' has a 180-degree phase difference compared to LC2, which fundamentally alters the timing characteristics of the pull-down holding circuit operation. This parameter change ensures that the TFTs experience reduced stress during alternate operation cycles, preventing threshold voltage shift while maintaining the alternative working mode.
2Reliability
If TFTs remain in high potential status for long time in pull-down holding circuit, then the circuit maintains its holding function, but the threshold voltage Vth of TFTs deflects forward causing circuit failure
Solution Approach 1:
The patent implements preliminary anti-action by configuring the second pull-down holding circuit with reverse clock signal LC2' that actively counteracts the threshold voltage forward deflection caused by the first circuit's operation. Before the damage accumulates in the first circuit, the second circuit is ready with an inverted signal that will reverse the stress effect, preventing irreversible damage while maintaining the holding function.
Data Source
AI summary
A GOA circuit is provided. The GOA circuit includes multiple cascaded GOA unit, each stage of the GOA unit is according to a N-staged GOA unit; the N-staged GOA unit comprises a pull-up control circuit, a pull-up circuit, a transmission circuit, a pull-down circuit, a pull-down holding circuit and a bootstrap capacitor; transmission the first reverse clock signal and the first clock signal of pull-down holding circuit have difference potential at each of the same clock, and the second reverse clock signal and the second clock signal of pull-down holding circuit have difference potential at each of the same clock. It could effective reverse correcting the problem of forward deflection of voltage threshold in the pull-down holding sub-circuit of single-stage GOA unit, such that enhances the reliability and stability of GOA circuit.