OLED Protection Circuit Voltage Detection Fault Isolation
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Solution Overview
Problem
OLED displays face issues with current flow to undesired positions when a pixel or driving circuit fails, affecting nearby pixel units due to the need for steady current control, which is not addressed by existing protection circuits.
Innovation Solution
A protection circuit with a determination circuit and coupling circuits that monitor voltage levels to couple or decouple terminals, ensuring current paths are maintained or disconnected based on predetermined voltage ranges, thereby isolating faulty pixel units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protection circuit is added to detect and disconnect faulty pixel units, then the reliability of the display system is improved, but the device complexity increases
Solution Approach 1:
The protection circuit is integrated into the existing pixel circuit structure by sharing the anode line and using the same driving transistor. The determination circuit utilizes the existing voltage detection capability of the pixel circuit, merging protection functions with display functions to avoid adding independent protection circuitry.
Solution Approach 2:
The driving transistor serves dual purposes: it drives the OLED during normal operation and acts as a switching element for protection during fault conditions. The anode line serves both as a power supply line for normal operation and as a detection line for fault detection, eliminating the need for separate protection circuit components.
2Speed
If voltage detection and rapid disconnection mechanisms are implemented, then the speed of fault response is improved, but the device complexity increases
Solution Approach 1:
The determination circuit continuously monitors the voltage at the anode in advance, maintaining readiness to detect fault conditions. The driving transistor is pre-configured as a switch that can rapidly transition from conduction to cutoff state, enabling immediate disconnection upon fault detection without requiring additional switching components.
Solution Approach 2:
The determination circuit provides continuous feedback on the anode voltage state to control the driving transistor's switching action. When the voltage indicates a short circuit condition, the feedback mechanism immediately triggers the driving transistor to cutoff, creating a rapid closed-loop protection response.
Data Source
AI summary
Embodiments of the present disclosure provide a protection circuit and method, a pixel circuit, and a display device. The protection circuit comprises a determination circuit, a first coupling circuit, a first terminal and a second terminal. The determination circuit is coupled to the first terminal and the first coupling circuit, and is configured to determine whether the voltage at the first terminal of the protection circuit belongs to one of a first predetermined range and a second predetermined range. The first coupling circuit is coupled to the first terminal, the second terminal and the determination circuit, and is configured to: couple the first terminal to the second terminal in response to the voltage at the first terminal belonging to the first predetermined range; and decouple the first terminal from the second terminal in response to the voltage at the first terminal belonging to the second predetermined range.