HDMI In Port Proxy Voltage Hot Plug Detection
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Solution Overview
Problem
End users may inadvertently connect a sink device to the HDMI In port instead of the HDMI Out port on intermediate devices like set-top boxes, leading to failure in video and audio transmission without clear indication of the error, as the ports appear physically similar and the HDMI standard does not provide a method for detecting incorrect connections.
Innovation Solution
An intermediate device is configured to apply a proxy voltage to its HDMI In port to simulate a hot plug event, allowing it to read the EDID from any connected device and generate an error message if it determines the device is a sink device incorrectly connected, switching from sink mode to source mode to output an error message instructing the user to reconnect the device to the correct port.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the HDMI In port operates in normal sink mode without detection capability, then the device structure remains simple, but incorrect connections cannot be detected and no error indication is provided to users
Solution Approach 1:
The HDMI In port dynamically switches between sink mode and source mode based on detection results. The port operates in sink mode during normal operation but transitions to source mode when a hot plug event is detected, enabling adaptive functionality that improves connection reliability without requiring permanently complex hardware
Solution Approach 2:
The system changes the operational parameters of the HDMI In port by switching its role between sink and source. This parameter change enables the port to perform detection functions when needed while maintaining simple sink mode operation during normal use, resolving the contradiction between reliability improvement and complexity increase
2Reliability
If the HDMI In port applies proxy voltage to detect hot plug events, then connection detection capability is improved, but energy consumption increases
Solution Approach 1:
The HDMI In port applies proxy voltage periodically rather than continuously to detect hot plug events. This periodic activation allows the system to maintain connection detection capability while significantly reducing energy consumption compared to continuous voltage application
Solution Approach 2:
The system uses the existing HPD line and hot plug event mechanism to perform detection, leveraging already-available infrastructure rather than requiring additional dedicated detection circuits. This self-service approach enables detection functionality while minimizing additional energy requirements
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively alerts the user to incorrect connections by generating an error message on the sink device, ensuring proper connection and preventing failure in video and audio transmission, by enabling detection of hot plug events even without a real +5V source and allowing the intermediate device to switch modes and output error messages.
Implementation Method 1
a proxy voltage is applied from an HDMI In port over an HDMI cable. The proxy voltage is sufficient to cause a hot plug event to occur.
Data Source
AI summary
A method is provided for indicating to a user that a sink device is incorrectly connected to a High Definition Multimedia Interface (HDMI) In port. In accordance with the method, a proxy voltage is applied from an HDMI In port over an HDMI cable. The proxy voltage is sufficient to cause a hot plug event to occur. A hot plug event condition is detected at the HDMI In port from a device that is connected to the HDMI In port via the HDMI cable. Extended Display Identification Data (EDID) is read from the device at the HDMI In port over the HDMI cable. In response to receipt of the EDID, a determination is made that the device is a sink device and an error message is generated in response to the determination.