Segmented Loudspeaker Voice Coil with Passive Rectification

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Solution Overview

Problem

Conventional loudspeakers face challenges in power handling and power consumption due to unnecessary heating of voice coil windings outside the air gap, as they do not significantly contribute to the electromotive force but are still powered, leading to inefficiencies.

Innovation Solution

A segmented voice coil design with center and auxiliary voice coil sections, where auxiliary driving signals are rectified to block currents not contributing to electromotive force, reducing power consumption and heating by using passive rectification units like diodes to attenuate or block currents in voice coil sections outside the air gap.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the entire voice coil is powered to ensure sufficient electromotive force, then the power handling capability is improved, but the power consumption increases and unnecessary heating occurs in sections outside the air gap

Engineering Contradiction:

Improvepower handling capabilityVSAvoidpower consumption

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The voice coil is divided into multiple sections: a first voice coil section positioned within the air gap and a second voice coil section positioned outside the air gap. Each section can be independently controlled, allowing the first section to be powered for electromotive force generation while the second section remains unpowered, thus eliminating unnecessary energy consumption and heating in the outer section.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sections of the voice coil are assigned different functional qualities based on their positions. The first section within the air gap is designed to interact with the magnetic field for electromotive force generation, while the second section outside the air gap is designed to remain unpowered since it does not contribute to force generation. This local differentiation optimizes power efficiency by applying power only where it is needed.

Inventive Principle:

Principle #3Local quality

2Power

If the entire voice coil is powered to ensure sufficient electromotive force, then the power handling capability is improved, but the heating in voice coil sections outside the air gap increases

Engineering Contradiction:

Improvepower handling capabilityVSAvoidvoice coil heating

Core Design Contradiction:

PowerVSTemperature

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent recognizes that the second voice coil section outside the air gap would normally generate heat without contributing to useful work. By deliberately excluding this section from power supply, the design converts the potential harm (wasted energy and heating) into a benefit (improved thermal management and efficiency) while maintaining sufficient power handling through optimized control of the first section within the air gap.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Loss of energy

If passive rectification units are added to block currents in voice coil sections outside the air gap, then power consumption is reduced, but the device complexity increases

Engineering Contradiction:

Improvepower consumptionVSAvoiddevice complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

Passive rectification units are incorporated into the circuit to automatically prevent current from reaching the second voice coil section outside the air gap. These units operate autonomously based on the electrical characteristics of the circuit, eliminating the need for active control mechanisms and complex signal processing while achieving the goal of reducing power consumption in non-productive sections.

Inventive Principle:

Principle #25Self-service

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

This design reduces power consumption and heat generation in loudspeakers by ensuring only voice coil sections within the air gap contribute to electromotive force, enhancing power handling and efficiency while maintaining simplicity suitable for both active and passive systems.

Implementation Method 1

When the coil windings are powered they interact with the magnetic field of the magnetic circuit 2 to produce an electromotive force translating the voice coil 1

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

said upper rectified driving signal is provided by attenuating, such as blocking, a first direction of current of said auxiliary driving signal by passive rectification

Methodology Applied

Scientific EffectPassive rectification: Diode

Data Source

PatentUS11102575B1Loudspeaker with passively controlled voice coil sections

Publication Date: 2021.08.24 TYMPHANY ACOUSTIC TECH (HUIZHOU) CO LTD

AI summary

A method for driving a voice coil of a loudspeaker may include providing a magnetic circuit having an air gap, providing a voice coil suspended in the air gap, and applying an audio signal to the voice coil to move the voice coil along a travelling axis. The voice coil comprises a center voice coil section, an upper voice coil section, and a lower voice coil section arranged on respective sides of the center voice coil section. A center driving signal is provided to the center voice coil and an upper rectified driving signal, attenuating a first direction of current, and a lower rectified driving signal, attenuating a second direction of current, are provided respectively to the upper and lower voice coil sections. The invention further relates to a voice coil driving system and a loudspeaker comprising a voice coil driving system.