Stage Circuit Transistor Switching for Low-Frequency Scanning
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Solution Overview
Problem
Existing display devices face challenges in maintaining reliability and minimizing power consumption, particularly at low driving frequencies due to leakage currents in scan drivers.
Innovation Solution
A stage circuit with a controller, such as a second transistor, that maintains a turn-on state during a display scan period and a turn-off state during a self-scan period, minimizing leakage currents and boosting the voltage of a second node to reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the display device is driven at a low driving frequency, then power consumption is reduced, but leakage current increases and reliability decreases
Solution Approach 1:
The patent applies dynamics by making the transistor switching state adjustable based on driving frequency. The controller dynamically changes the transistor from turn-on state during display scan period to turn-off state during self-scan period, adapting the circuit behavior to operating conditions. This dynamic adjustment resolves the contradiction by preventing leakage current accumulation at low frequencies while maintaining normal operation at higher frequencies.
Solution Approach 2:
The patent implements periodic action through the cyclic switching of the transistor between turn-on and turn-off states corresponding to the periodic display scan and self-scan periods. This periodic control ensures that the transistor conducts during the display scan period when signal transmission is needed and turns off during the self-scan period to prevent leakage, thereby maintaining reliability across varying driving frequencies.
2Use of energy by moving object
If the display device is driven at a low driving frequency, then power consumption is reduced, but leakage current increases
Solution Approach 1:
The controller dynamically adjusts the transistor state based on the driving frequency and operational period. At low driving frequencies, the transistor is turned off during self-scan periods to prevent leakage current accumulation, while still allowing operation during display scan periods. This dynamic control enables low power consumption without sacrificing reliability by eliminating the harmful leakage effect.
Solution Approach 2:
The patent converts the potentially harmful leakage current into a beneficial control mechanism. By strategically turning off the transistor during self-scan periods, the circuit uses the absence of current flow to prevent leakage accumulation. This approach transforms what could be a harmful effect into a useful control feature that maintains signal integrity and prevents degradation over time.
3Reliability
If a controller is added to control the electrical connection, then leakage current is minimized, but device complexity increases
Solution Approach 1:
The controller is designed to perform multiple functions: it controls the transistor switching state, manages the electrical connection between input and output nodes, and adapts to different driving frequencies. By making the controller multi-functional, the patent reduces the need for separate dedicated components for each function, thereby minimizing the increase in device complexity while achieving reliable leakage current control.
Solution Approach 2:
The controller acts as an intermediary component between the input unit and the transistor, mediating the electrical connection. This intermediary role allows the controller to manage the timing and state of the transistor without requiring complex direct control circuits. The mediator approach simplifies the overall circuit architecture by using a single control unit to coordinate multiple functions.
Data Source
AI summary
A stage circuit includes an output unit which supplies a scan signal to an output terminal in response to a voltage of a first node and a second node, an input unit which outputs a carry signal or a start signal input to a first input terminal in response to a clock signal, a first transistor connected between the input unit and the second node and set to a turn-on state during a driving period, and a controller connected between the input unit and the first transistor or between the first transistor and the second node, where the controller controls an electrical connection between the input unit and the second node.