Shift Register Driver Circuit for Floating Gate Noise Suppression
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Solution Overview
Problem
Conventional driver circuits experience malfunctions due to timing deviations in transistor switching operations, particularly when using amorphous semiconductor transistors, which are prone to deterioration, leading to noise-induced issues and threshold voltage changes.
Innovation Solution
A driver circuit design incorporating a shift register with specific flip-flop circuits that include multiple transistors and capacitors, where the phase of clock signals is opposite and the potential difference between signal states is greater than the transistor threshold voltage, ensuring stable operation and reducing noise effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If amorphous semiconductor transistors are used in flip-flop circuits, then device complexity is reduced and manufacturing cost decreases, but transistor deterioration occurs leading to timing deviation and malfunctions
Solution Approach 1:
The patent applies preliminary action by setting the gate terminal of the pull-up transistor to a fixed potential (ground or power supply potential) during the non-selection period before noise or deterioration can cause malfunctions. This preventive measure ensures that even if transistor characteristics change over time, the circuit maintains stable operation by eliminating the floating state that leads to timing deviations.
2Device complexity
If the gate terminal of the pull-up transistor is left floating during non-selection period, then device complexity is minimized, but noise adversely affects the gate terminal potential causing malfunctions
Solution Approach 1:
The patent applies preliminary anti-action by introducing a countermeasure (connecting the gate terminal to a fixed potential) that directly opposes the harmful effect of noise. By preemptively eliminating the floating state, the circuit becomes immune to noise-induced malfunctions without requiring complex shielding or filtering mechanisms.
3Ease of manufacture
If transistor threshold voltage changes due to deterioration, then manufacturing simplicity is maintained, but switching timing deviates from desired timing causing malfunctions
Solution Approach 1:
The patent applies preliminary action by establishing a stable gate potential before transistor deterioration can affect switching timing. By fixing the gate terminal potential during the non-selection period, the circuit ensures consistent switching behavior even as transistor threshold voltages drift over time, thereby maintaining timing accuracy without requiring precision manufacturing.
Data Source
AI summary
To suppress malfunctions in a shift register circuit. A shift register having a plurality of flip-flop circuits is provided. The flip-flop circuit includes a transistor 11, a transistor 12, a transistor 13, a transistor 14, and a transistor 15. When the transistor 13 or the transistor 14 is turned on in a non-selection period, the potential of a node A is set, so that the node A is prevented from entering into a floating state.