Adaptive Headset Connection Detection via Impedance Measurement

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Solution Overview

Problem

The increasing complexity of intercom systems and portable audio devices has made it difficult to determine whether a headset is connected to an active intercom or radio, due to variations in electrical characteristics and behavior, leading to issues with electrical incompatibility and power conservation.

Innovation Solution

An apparatus and method that includes a conductor with a voltage sensor and controller to monitor signal activity, inject current, and calculate an adaptive threshold voltage to determine if the headset is connected to an active intercom or radio, allowing for efficient power management and compatibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the headset continuously monitors connection status using traditional methods, then connection detection capability is maintained, but power consumption increases and reliability decreases due to electrical characteristic variations

Engineering Contradiction:
Improveconnection detection reliabilityVSAvoidheadset power consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system performs impedance measurements at periodic intervals rather than continuously, allowing the headset to enter low-power states between measurements. The controller is configured to periodically measure impedance values across the conductor, comparing current measurements against stored thresholds to detect connection status changes while conserving battery power during idle periods.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent replaces traditional mechanical or simple electrical connection detection methods with an electrical impedance measurement system. By measuring the impedance characteristics of the conductor, the system can reliably detect whether a device is connected without requiring continuous power or complex mechanical switches, thereby improving reliability while managing power consumption.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If the headset uses fixed threshold voltage for connection detection, then detection simplicity is maintained, but measurement precision deteriorates due to electrical characteristic variations in different intercom systems

Engineering Contradiction:
Improveconnection detection accuracyVSAvoiddetection algorithm complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs preliminary impedance measurements during initialization or calibration phases to establish baseline characteristics for different intercom systems. These preliminary measurements allow the system to store multiple threshold values corresponding to different device types, enabling more accurate detection without requiring complex real-time analysis during normal operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamic threshold adjustment where the detection threshold is not fixed but adapts based on the measured impedance characteristics. The controller compares impedance values against multiple stored thresholds and selects the appropriate threshold based on the detected pattern, allowing the system to accommodate variations in electrical characteristics across different intercom and radio systems while maintaining detection accuracy.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If the headset supports simultaneous coupling to intercom and portable audio devices, then versatility is improved, but electrical incompatibility problems increase

Engineering Contradiction:
Improvedevice compatibilityVSAvoidelectrical compatibility
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system monitors impedance parameters to detect the type of connected device and dynamically adjusts its electrical characteristics accordingly. By measuring the impedance profile of the connected device, the headset can identify whether it is connected to an intercom system, radio, or portable audio device, and then adjust its output voltage levels and current characteristics to match the requirements of the specific device type, thereby preventing electrical incompatibility issues.

Inventive Principle:
Principle #35Parameter changes

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 reliable detection of headset connections to intercom systems, ensuring proper operation and power conservation, thereby improving ease of use and reducing electrical incompatibility issues.

Implementation Method 1

a voltage sensor coupled to the conductor to measure a voltage present on the conductor relative to a ground conductor

Methodology Applied
Scientific EffectVoltage measurement: Ohm's Law

Implementation Method 2

inject a current into the conductor and operate the voltage sensor to obtain a measure of a voltage on the conductor while the current is injected into the conductor

Methodology Applied
Scientific EffectElectrical current injection: Conduction (electrical)

Data Source

PatentEP2594022B1Headset connection sensing and zero power on button
Publication Date: 2015.04.08 BOSE CORP
  • EP2594022B1 patent drawingFigure 1
  • EP2594022B1 patent drawingFigure 2
  • EP2594022B1 patent drawingFigure 3

AI summary

A normally-open pushbutton switch is coupled to and cooperates with a pair of MOSFETs to provide a power on switch function for a personal audio device that does not require power to be drawn from a power source to monitor the pushbutton switch while awaiting operation of the pushbutton switch to cause the personal audio device to be powered on. A controller of a personal audio device, on multiple occasions, monitors a conductor by which it is able to be coupled to another device for the end to an instance of signal activity, and following the end of signal activity, injects a current into the conductor and measures the resulting voltage to calculate an adaptive threshold voltage and to compare the measured voltage to the adaptive threshold to determine at least whether or not the conductor of the personal audio device is coupled to another device.