AMOLED Pixel Driving Circuit with Alternating Initialization Signal
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Solution Overview
Problem
The existing AMOLED pixel driving circuits face issues with threshold voltage compensation, leading to leakage currents and distortion in gate and source voltages, affecting the stability and accuracy of light emission compensation data.
Innovation Solution
A pixel driving system with a 4T1C architecture and an initialization voltage supply module that provides a high and low alternating initialization signal, effectively stabilizing the current through the organic light emitting diode by compensating the threshold voltage of the driving thin film transistor, reducing leakage current, and enhancing compensation data stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a low-level initialization voltage is used in the AMOLED pixel driving circuit, then the circuit can be kept simple, but the source voltage of the fourth thin film transistor becomes lower than the gate and source voltage of the second thin film transistor, causing leakage current that distorts compensation data and affects compensation effect
Solution Approach 1:
The initialization voltage is changed from a static low level to a dynamic signal that alternates between high and low levels according to different working stages. During the compensation stage, a high-level initialization voltage is applied to ensure proper voltage relationships and prevent leakage current, while during other stages, a low-level voltage is used to maintain circuit simplicity.
Solution Approach 2:
The initialization voltage parameter is changed from a fixed low level to a variable parameter that switches between high and low levels based on the operating stage. This parameter change allows the circuit to optimize performance during different stages: using high level during compensation to prevent leakage and low level during other stages to maintain simplicity.
2Ease of operation
If the initialization voltage is always at low electrical level, then the circuit operation is simplified, but the gate and source of the second thin film transistor generate leakage current causing distortion in compensation data
Solution Approach 1:
The initialization voltage is applied periodically with different levels corresponding to different working stages. A high-level initialization voltage is applied during the compensation stage to eliminate leakage current and ensure accurate compensation data, while low-level voltage is applied during other stages to maintain ease of operation.
Solution Approach 2:
The initialization voltage is applied in advance before the compensation stage to prepare the transistor gates and sources for accurate compensation. By setting the initialization voltage to a high level before compensation begins, the circuit prevents leakage current from affecting the subsequent compensation data accuracy.
3Reliability
If a high-level initialization voltage is applied during light emission stage, then the leakage current is reduced and compensation data stability is improved, but the circuit requires more complex voltage control
Solution Approach 1:
The circuit uses stage detection feedback to determine when to apply high-level versus low-level initialization voltage. By monitoring the working stage through feedback signals, the control circuit automatically adjusts the initialization voltage level appropriately, improving compensation data stability during critical stages while managing voltage control complexity through automated stage-based switching.
Data Source
AI summary
The present application provides a pixel driving system of AMOLED and a pixel driving method of AMOLED. The pixel driving system of AMOLED includes a pixel driving circuit of a 4T1C architecture, and an initialization voltage supply module electrically connected to the pixel driving circuit, by providing a high level of an initialization signal from the initialization voltage supply module at the light emission stage in the pixel driving circuit to effectively compensate the threshold voltage of the driving thin film transistor, so that the current flowing through the organic light emitting diode is stabilized while reducing the leakage current of the gate and the source of the driving thin film transistor in the light emission stage, the stability of the compensation data in the light emission stage, to enhance the compensation effect.