Headset Power Delivery via Audio Channel Multiplexing
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Solution Overview
Problem
Existing methods for providing power to headsets through standard connectors face compatibility issues with existing terminals and headsets, often resulting in increased costs, maintenance burdens, and potential distortion or reduction in audio quality due to shared signal channels.
Innovation Solution
A method that amplitude modulates a carrier signal with a modulation signal complementary to the audio signal's time-varying amplitude, creating a composite signal with a limited maximum amplitude, allowing power to be transmitted over existing audio channels without disrupting audio quality or requiring hardware changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If power is supplied to the headset through additional conductors and connector contacts, then power delivery capability is improved, but compatibility with existing terminals and headsets deteriorates
Solution Approach 1:
The existing audio conductor is made multi-functional by multiplexing both audio signals and power delivery over the same physical medium. The system maintains compatibility with standard TRS connectors while enabling power delivery through intelligent signal processing and detection mechanisms that allow the terminal and headset to negotiate power delivery capability over the audio interface.
Solution Approach 2:
The system changes the electrical parameters of the audio signal to enable power delivery. By modulating the audio signal with high-frequency carriers and using differential signaling, the system can deliver power over the audio conductor while maintaining audio functionality. The terminal detects headset impedance characteristics to determine power delivery capability and adjusts signaling parameters accordingly.
2Device complexity
If power and audio signals share a single conductor through multiplexing, then device complexity is reduced, but audio signal quality deteriorates due to clipping and distortion
Solution Approach 1:
The system uses periodic high-frequency carrier waves to modulate the power signal. By switching the power delivery in synchronization with the audio signal cycles and using differential signaling, the system delivers power while maintaining audio signal integrity. The periodic nature of the carrier allows for efficient power transfer without causing clipping or distortion in the audio path.
Solution Approach 2:
The system introduces an intermediary modulation scheme that separates power delivery from audio signal transmission. By using high-frequency carriers as an intermediary medium, the system can deliver power through the audio conductor without directly interfering with the audio signal. The modulation and demodulation processes act as intermediaries that allow simultaneous power and audio signal transmission.
3Reliability
If a battery is placed in the headset to provide power, then power delivery reliability is improved, but headset weight and size increase
Solution Approach 1:
The system extracts the power source from the headset and relocates it to the terminal. By removing the battery from the headset and providing power through the audio interface from the terminal, the system eliminates the weight and size burden of battery components while maintaining continuous power supply. The terminal acts as the external power source, delivering electricity through the audio conductor to the headset's active components.
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
Enables efficient power transfer to headsets while maintaining compatibility with existing terminals and headsets, avoiding the need for battery replacement and reducing maintenance costs, while preserving audio signal integrity.
Implementation Method 1
generating a power signal by amplitude modulating a carrier signal with a modulation signal that is formed in a complementary fashion to the time-varying amplitude of the audio signal
Implementation Method 2
The headset includes a power extractor configured to extract and rectify the modulated power signal from the composite audio signal
Data Source
AI summary
A power delivery method and system for powering a headset. A power signal is combined with an audio signal to form a composite signal that is communicated over a shared channel to the headset. The power signal is generated by modulating a carrier signal with a modulation signal. The modulation signal is derived from the amplitude of the audio signal so that the peak levels of the composite signal do not exceed the maximum allowable output of an audio I/O circuit driving the headset.