Gate Drive Circuit Layout to Cut Leakage in Touch Detection
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Solution Overview
Problem
Existing drive circuits require a charging circuit for each unit circuit to recharge internal wiring lines to a first potential before the scanning period starts, leading to large unit circuits due to current leakage during non-scanning periods.
Innovation Solution
A drive circuit design that includes unit circuits with specific transistor configurations to maintain the potential of a first node during stop periods, eliminating the need for a charging circuit by reducing current leakage through transistors T3 and T4, thereby downsizing the unit circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a charging circuit is added to recharge the internal wiring line before the scanning period starts, then the potential of the internal wiring line can be maintained, but the unit circuit size increases
Solution Approach 1:
The patent extracts the charging function from a separate charging circuit and integrates it into the existing transistor structure. Specifically, the first transistor's source electrode is connected to the first potential, allowing it to serve dual purposes: driving the scanning line during scanning periods and charging the internal wiring line during non-scanning periods, thereby eliminating the need for a dedicated charging circuit
Solution Approach 2:
The first transistor is designed to perform multiple functions: it acts as the driving transistor during scanning periods and simultaneously serves as a charging transistor during non-scanning periods by connecting its source electrode to the first potential. This multi-functionality reduces the overall number of components needed in the unit circuit
2Productivity
If transistors T3 and T4 are used to control the internal wiring line during non-scanning period, then the scanning can be stopped, but current leaks from the internal wiring line
Solution Approach 1:
The patent introduces a second transistor as an intermediary element between the internal wiring line and the first potential. The second transistor is controlled by a control signal to selectively connect or disconnect the internal wiring line from the first potential during non-scanning periods, thereby preventing current leakage while maintaining the ability to control scanning
Solution Approach 2:
The circuit employs dynamic control of transistor states based on the scanning period requirements. During non-scanning periods, the second transistor is turned on to connect the internal wiring line to the first potential through the controlled path, preventing leakage. During scanning periods, the transistor states are dynamically changed to enable proper driving function
Data Source
AI summary
A unit circuit of a gate drive circuit includes first and second nodes and first to fifth transistors. The first transistor outputs a drive signal from a terminal thereof in response to a clock signal. A set signal is input to the second transistor, which charges the first node. A reset signal is input to the third transistor, which discharges the first node. The fourth transistor is located between the first node and the second node and is in an off state during a touch detection period. The first node is connected to a gate electrode of the fifth transistor, and the fifth transistor charges the second node when a potential of the first node becomes high level or more. A signal that is a gate-on voltage during the touch detection period and is a gate-off voltage during a display period is input to the third transistor.