Accessory Power Management via Impedance Detection

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Solution Overview

Problem

Battery-powered accessories like headphones with active noise reduction circuitry waste power when disconnected from an audio source or when the audio source is powered down, leading to inefficient battery usage.

Innovation Solution

An electrical conductor is used to connect the audio source and accessory, injecting a second signal to measure impedance, allowing battery power reduction when the accessory is disconnected or the audio source is off, thereby shutting off or putting the accessory in standby mode to conserve power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the accessory remains powered on to ensure quick wake-up capability, then the response speed is improved, but the battery power consumption increases

Engineering Contradiction:

Improvewake-up response speedVSAvoidbattery power consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic power management by transitioning the accessory between different operational states (full power, standby, and off) based on real-time detection of audio source connection status. The system dynamically adjusts its power consumption profile while maintaining the ability to quickly resume operation when needed.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system performs preliminary detection of the audio source connection state before fully activating power-consuming components. By detecting impedance changes on the conductor beforehand, the accessory can avoid unnecessary power consumption while ensuring it's ready to activate quickly when a valid connection is detected.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the accessory continuously monitors connection status, then the reliability of power management is improved, but the battery power consumption increases

Engineering Contradiction:

Improvepower management reliabilityVSAvoidbattery power consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

Instead of continuous monitoring, the system employs periodic impedance detection through injection of test signals at intervals. This approach maintains reliable detection of connection status while significantly reducing power consumption compared to continuous monitoring schemes.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The accessory uses its own existing audio conductor and electrical components to perform self-diagnosis of connection status. By utilizing the same conductor that carries audio signals for impedance detection, the system avoids requiring additional dedicated monitoring hardware and the power it would consume.

Inventive Principle:

Principle #25Self-service

3Measurement precision

If impedance detection is performed to determine connection state, then the accuracy of connection detection is improved, but the battery power consumption increases

Engineering Contradiction:

Improveconnection detection accuracyVSAvoidbattery power consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system measures impedance by injecting test signals at different frequency levels (including ultrasonic frequencies above the audio passband) and analyzing the resulting voltage responses. By varying the frequency parameter of test signals, the system achieves accurate connection detection while using brief measurement intervals that minimize overall power consumption.

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

Effectively reduces battery power consumption by determining the connection state with the audio source, allowing the accessory to enter a low-power standby or shut-off state, thereby extending battery life and ensuring quick wake-up capabilities.

Implementation Method 1

The conductor is capable of conducting a first electrical signal, containing audio information from the audio source, to the accessory

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

The applying step can include a step of injecting an electrical current into the electrical conductor, and a step of measuring a voltage on the electrical conductor

Methodology Applied

Scientific EffectVoltage measurement: Ohm's Law

Implementation Method 3

An amount of battery power supplied to the accessory is reduced when the measured aspect meets a predetermined condition

Methodology Applied

Scientific EffectPower reduction:

Data Source

PatentUS7983427B2Method and apparatus for conserving battery power

Publication Date: 2011.07.19 BOSE CORP

AI summary

A method of conserving battery power includes providing an electrical conductor that is connectable between an audio source and an accessory of the audio source. The conductor is capable of conducting a first electrical signal, containing audio information from the audio source, to the accessory. A second electrical signal is applied to the conductor when the first electrical signal is not present on the conductor. An aspect of the second electrical signal is measured while it is being applied to the conductor. An amount of battery power supplied to the accessory is reduced when the measured aspect meets a predetermined condition.