HDMI HPD Pin Charging for Mobile Devices

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Solution Overview

Problem

Existing methods for charging mobile devices with an HDMI interface require users to connect separate power chargers, which is inconvenient, especially on miniaturized devices where connectors are close together, necessitating the use of two cables.

Innovation Solution

The method involves transmitting and receiving charging current via the Hot Plug Detect (HPD) pin of an HDMI cable, allowing a mobile device to be charged by simply connecting an HDMI cable, with the HDMI Sink providing a charging current through the HPD line and the Source detecting charging capability via the Data Display Channel (DDC) bus.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a separate power charger is connected to the USB connector of the mobile device, then the device can be charged, but the user has to connect two cables which is inconvenient and can even be impossible due to the nearness of connectors on miniaturized mobile devices

Engineering Contradiction:

ImproveCharging convenienceVSAvoidNumber of connectors and cables

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent combines the power charging function with the HDMI interface by utilizing the HPD line, which is already part of the HDMI connection. This merging of functions allows the same cable to serve both video/audio transmission and power charging purposes, eliminating the need for a separate power charger connection.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The HDMI interface is made multi-functional by enabling it to perform both its original function (video/audio transmission) and an additional function (power charging). The HPD line, originally designed for hot-plug detection, is repurposed to also carry charging current, making the HDMI cable a universal connector for multiple purposes.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If the HPD line is used for charging current transmission, then the charging function is integrated into the HDMI interface, but the original HPD signal functionality must be maintained

Engineering Contradiction:

ImproveCharging capability integrationVSAvoidSignal detection accuracy

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies different characteristics to different parts of the HPD line usage. During normal operation, the HPD line maintains its original signal level for hot-plug detection. During charging operation, the line is repurposed to carry charging current. This local differentiation of function allows the same physical line to serve multiple purposes without conflict.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system dynamically switches the function of the HPD line based on operational mode. The mobile device can detect whether the connected HDMI device supports charging and accordingly switch between using the HPD line for signal detection or for power reception. This dynamic adaptability ensures both original and new functions work reliably.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS8841886B2Power charging of mobile devices via a HDMI interface

Publication Date: 2014.09.23 NXP BV

AI summary

A method is provided of charging a mobile device by a charger device, comprising transmitting and receiving a charging current via the Hot Plug Detect (HPD) pin of an HDMI cable connected between the mobile device and the charging device. The HDMI source device (the mobile device) and the HDMI sink device (the charger device) are also provided.