Notebook Display Port Detection Circuit Using Blanking Interval Signals
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Solution Overview
Problem
Conventional methods for detecting the disconnection of an external display device from a notebook computer require periodic CPU interrogation, reducing system performance as they rely on software-based methods that utilize I2C communication, necessitating continuous CPU execution to monitor connection status.
Innovation Solution
A detecting circuit that generates an interrupt signal to the CPU when the external display device is disconnected, utilizing the voltage level of the red, green, or blue signal during the blanking interval of the vertical or horizontal synchronous signal to automatically switch the image to the notebook computer's LCD monitor, eliminating the need for periodic CPU interrogation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If software-based I2C communication is used to detect external display device connection status, then the detection can be implemented, but the CPU performance is reduced due to periodic interrogation requirements
Solution Approach 1:
The patent introduces an embedded controller as an intermediary component that handles the detection of external display device connection status. The embedded controller independently monitors the connection status without requiring CPU intervention, thereby resolving the contradiction by maintaining reliable detection while freeing CPU resources for other tasks.
Solution Approach 2:
The embedded controller performs self-service by autonomously detecting connection status changes and generating interrupt signals to the CPU only when necessary. This self-monitoring capability eliminates the need for continuous CPU-based periodic interrogation, thus maintaining detection reliability while preserving CPU performance.
2Reliability
If periodic CPU interrogation is implemented to monitor connection status, then connection detection is achieved, but system performance deteriorates due to continuous monitoring requirements
Solution Approach 1:
The patent transforms the continuous periodic CPU interrogation into event-driven periodic action. The embedded controller performs monitoring continuously in the background, but only triggers CPU intervention when a connection status change is detected. This approach maintains reliable monitoring while reducing overall system resource consumption by eliminating unnecessary periodic CPU involvement.
3Ease of operation
If manual hot key operation is required for image switching, then user control is maintained, but ease of operation is reduced due to additional user intervention steps
Solution Approach 1:
The patent implements automatic feedback-based image switching. The embedded controller continuously monitors connection status and automatically triggers image switching when a disconnection is detected, eliminating the need for manual hot key operation. This feedback mechanism maintains ease of operation by making the system responsive to connection changes without requiring user intervention, while simultaneously increasing automation.
Data Source
AI summary
A notebook computer having a display port capable of outputting a vertical synchronous signal, a horizontal synchronous signal, a red signal, a green signal, and a blue signal to an external display device to display an image is disclosed. The notebook computer includes a monitor device built in the notebook computer, an embedded controller capable of outputting an enable signal and a detecting circuit receiving a first signal, a second signal and the enable signal. The first signal is the vertical synchronous signal or the horizontal synchronous signal. The second signal is the red signal, the green signal or the blue signal. When the external display device is disconnected with the display port, the detecting circuit may determine the second signal according to the actuation of the enable signal at a blanking interval of the first signal and switch the image to the monitor device automatically.