OLED Control Signal Circuit Pulse Deformation
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Solution Overview
Problem
Existing OLED display control signal circuits suffer from output pulse deformation due to floating states caused by clock and Q signals having low levels simultaneously, leading to abnormal outputs.
Innovation Solution
A control signal circuit with driving units and reverse circuits generates a first output pulse with the same waveform as the clock signal, and reverses it to produce a second output pulse, using a clock signal with an opposite waveform to prevent floating states and ensure normal output pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the clock signal and Q signal both have low levels simultaneously, then the transistors are turned off, but the output node enters a floating state causing pulse deformation
Solution Approach 1:
An intermediate node is introduced between the clock signal and Q signal paths to coordinate their timing. This intermediate node ensures that when one signal is low, the other is high, preventing the floating state condition. The intermediary acts as a mediator that resolves the conflict between the two control signals.
Solution Approach 2:
The waveform of one of the control signals is inverted so that it has the opposite logic levels compared to the original design. By inverting the clock signal waveform, the condition where both signals are low simultaneously is eliminated, as one signal will always be high when the other is low.
2Manufacturing precision
If the output node is left floating during transistor off-state, then the circuit structure is simple, but the output pulse becomes deformed
Solution Approach 1:
The intermediate node serves as a mediator that actively controls the output node state. Instead of leaving the output node floating, the intermediary ensures it maintains a defined logic level by coordinating the timing of control signals, thereby preventing pulse deformation without adding complex stabilization circuits.
Solution Approach 2:
The control signals are timed in advance through the intermediate node to prevent the floating state from occurring. By preliminarily coordinating the signal transitions, the circuit ensures that the output node never enters an undefined state, maintaining waveform accuracy throughout operation.
3Speed
If NMOS transistors are used with opposite waveform control signals, then the switching performance is improved, but the risk of floating state and pulse deformation increases
Solution Approach 1:
The intermediate node acts as a coordinator between the NMOS transistor control signals. By mediating the timing and levels of the opposite waveform signals, it ensures that the high-speed switching of NMOS transistors does not lead to floating states, thus maintaining both speed and signal integrity.
Solution Approach 2:
The intermediate node applies preliminary anti-action by pre-coordinating the control signals to prevent the harmful floating state condition before it can occur. This anticipatory coordination ensures that the fast-switching NMOS transistors operate reliably without causing pulse deformation.
Data Source
AI summary
A display device includes a display panel; and a control signal circuit that supplies a control signal to the display panel. The controls signal circuit includes a plurality of driving units and a plurality of reverse circuit, wherein the driving units are supplied with a clock signal and generate a first output pulse that has the same waveform as the clock signal, and wherein the reverse circuit reverses the first output pulse to generate a second output pulse that is an output of the control signal circuit.