Shift Register Flip-Flop Circuit for Off-Leakage Current Control
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Solution Overview
Problem
Existing shift register circuits for display devices face challenges in maintaining stable operation while minimizing manufacturing costs, particularly under low-frequency driving conditions, where off-leakage currents can cause erroneous operations due to floating node potentials.
Innovation Solution
Incorporating a control element that manages current flow between the gate and power supply of output transistors to counteract off-leakage currents, ensuring consistent potential and reducing the probability of erroneous operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional shift register circuit is used without additional control elements, then the device complexity and manufacturing cost are reduced, but off-leakage currents cause floating node potentials leading to erroneous operations and reduced reliability
Solution Approach 1:
A control element (third field-effect transistor) is introduced as an intermediary between the gate of the output field-effect transistor and the power supply. This control element mediates the flow of electric current to counteract off-leakage currents from the first and second field-effect transistors, thereby stabilizing the gate potential and preventing erroneous operations without requiring fundamental circuit redesign
Solution Approach 2:
The control element is configured to operate in advance during periods when the first and second field-effect transistors are off, proactively counteracting off-leakage currents before they can cause floating node potentials and erroneous operations. By continuously managing current flow during these critical periods, the circuit prevents reliability issues before they occur
2Use of energy by moving object
If the frame frequency is reduced to save power consumption, then energy efficiency improves, but off-leakage currents have more time to affect floating nodes increasing the probability of erroneous operations
Solution Approach 1:
The control element provides continuous current management between the gate and power supply throughout the operating cycle, ensuring that even during extended periods between frames at low frequency operation, off-leakage currents are continuously counteracted. This continuous action maintains gate potential stability regardless of the extended time intervals caused by low-frequency driving
Solution Approach 2:
The control element creates a feedback mechanism where the current flow from the power supply through the control element counterbalances the off-leakage currents from the first and second field-effect transistors. This feedback loop automatically adjusts to maintain stable gate potential conditions even when operating at reduced frame frequencies where leakage accumulation would normally be problematic
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively maintains stable operation of shift registers by minimizing the impact of off-leakage currents, thereby enhancing the reliability of display devices under low-frequency driving conditions.
Implementation Method 1
The control element is configured to operate to make an electric current flow between the gate and a power supply in the opposite direction of an off-leakage current
Data Source
AI summary
A circuit includes a flip-flop included in a multi-stage shift register and a control element. The flip-flop includes an output field-effect transistor, a first field-effect transistor configured to operate to supply one of a high potential and a low potential to the gate of the output field-effect transistor, and a second field-effect transistor configured to operate to supply the other one of the high potential and the low potential to the gate of the output field-effect transistor. The control element is configured to operate to make an electric current flow between the gate and a power supply in the opposite direction of an off-leakage current from at least either one of the first field-effect transistor and the second field-effect transistor in a period where the first field-effect transistor and the second field-effect transistor are off.