Shift Register Noise Reduction Circuit for Stable Display Scanning
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Solution Overview
Problem
The output of shift register units in drive control circuits for display panels is unstable, leading to abnormal display due to issues such as screen flickering and short circuits between reference voltage signal terminals.
Innovation Solution
A shift register unit design incorporating an input circuit, control circuits, output circuits, and a noise reduction circuit, including transistors and capacitors, to stabilize signal output and prevent simultaneous conduction of output circuits, thereby reducing screen flickering and short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cascaded shift register units are used for scanning drive, then the display panel can be driven, but the output signal becomes unstable causing screen flickering
Solution Approach 1:
The shift register unit is segmented into multiple independent circuits: input circuit, control circuit, first output circuit, second output circuit, and noise reduction circuit. Each circuit has a specific function, and the segmentation allows independent optimization and stability control of each part, preventing signal instability from propagating through the entire system.
Solution Approach 2:
The noise reduction circuit acts as an intermediary between the control circuit and the second output circuit. It receives a noise reduction signal and uses it to control the conduction state of the second output circuit, thereby mediating potential signal conflicts and preventing simultaneous conduction that would cause instability.
2Productivity
If multiple output circuits are used to provide reference voltage signals, then the output can be enhanced, but short circuits between reference voltage signal terminals occur
Solution Approach 1:
The second output circuit's conduction state is dynamically controlled by the noise reduction signal. The circuit can switch between conducting and non-conducting states based on the noise reduction signal, allowing the system to adaptively prevent short circuits while maintaining output functionality when needed.
Solution Approach 2:
The noise reduction circuit receives a noise reduction signal (which may be derived from system state feedback) and uses it to adjust the conduction state of the second output circuit. This feedback mechanism ensures that the output circuits operate in a controlled manner that prevents harmful short circuits.
3Productivity
If the second output circuit continuously outputs signals, then the drive capability is maintained, but screen flickering increases
Solution Approach 1:
The second output circuit operates in a controlled periodic manner rather than continuously. The noise reduction signal periodically controls the conduction state of the second output circuit, allowing it to output signals only when appropriate and remain non-conducting at other times, thereby reducing flickering while maintaining necessary drive capability.
Data Source
AI summary
Disclosed are a shift register unit (SRn), a drive control circuit, a display apparatus and a driving method. The shift register unit includes an input circuit, a control circuit, a first output circuit a second output circuit, and a noise reduction circuit configured, in response to a signal from the noise reduction signal terminal (VEL), to provide a signal from a third reference voltage signal terminal (V3) to the second node (N2) and to control the second output circuit to stop signal output.