Speaker Gain Control Under Transient Power and Thermal Constraints
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Solution Overview
Problem
Conventional temperature protection methods for miniature speakers in portable devices often result in over-protection, leading to reduced speaker volume and sudden changes in sound quality due to the use of fixed gain attenuation and steady-state power thresholds that do not accurately account for transient power and voice coil temperature.
Innovation Solution
Implementing a dynamic gain control method that calculates a transient power threshold based on real-time voice coil temperature and input power, using a joint power and temperature constraint policy to adjust the gain smoothly and prevent over-protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If steady-state power threshold is used to control transient input power, then speaker temperature is protected, but speaker volume is reduced due to over-protection
Solution Approach 1:
The patent applies dynamics by transitioning from a static steady-state power threshold to a dynamic transient power threshold that adapts in real-time based on voice coil temperature. The control gain is continuously adjusted according to the relationship between transient power and temperature, enabling the system to maintain optimal speaker volume while providing appropriate temperature protection. This resolves the contradiction by making the protection mechanism adaptive rather than fixed.
Solution Approach 2:
The patent changes the parameter from steady-state power threshold to transient power threshold, and from fixed gain attenuation to dynamic gain control. By calculating the transient power threshold based on real-time temperature and power conditions, and adjusting the control gain dynamically, the system optimizes both temperature protection and speaker volume output, resolving the over-protection issue.
2Reliability
If fixed gain attenuation is applied for temperature protection, then speaker temperature is controlled, but sound quality deteriorates due to sudden changes
Solution Approach 1:
The patent replaces fixed gain attenuation with dynamic gain control that continuously adjusts the control gain based on real-time temperature and power conditions. This dynamic adjustment ensures smooth transitions in gain values, preventing sudden changes in sound quality while maintaining effective temperature control of the speaker.
3Device complexity
If steady-state power threshold is used, then temperature protection is simplified, but transient power cannot be accurately controlled
Solution Approach 1:
The patent changes the power threshold parameter from steady-state to transient power threshold. The transient power threshold is calculated in real-time based on the relationship between voice coil temperature and input power, enabling accurate control of transient power conditions while maintaining a relatively simple control architecture through the use of established thermal models.
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 approach maximizes speaker volume while protecting the voice coil from overheating, ensuring a stable and optimal auditory experience by accurately distinguishing various signals and preventing sudden volume changes.
Implementation Method 1
a moving coil speaker (that is also referred to as an electro-dynamic speaker, and has a working principle that an input current generates a changing magnetic field through a coil, so that a diaphragm of the speaker vibrates to generate sound)
Implementation Method 2
The moving coil speaker has characteristics of having very low electro-acoustic conversion efficiency (usually less than 1%) and generating heat
Data Source
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AI summary
The present invention provides an audio signal processing method. In the method, a power constraint is implemented based on a power of a current input signal and a currently calculated transient power threshold, and a temperature constraint is implemented based on a current voice coil temperature and an upper operating temperature limit of a speaker. A joint gain control policy with the two constraints and a dynamic gain control calculation method are proposed, to resolve problems of speaker over-protection and output gain sudden changes. Therefore, subjective experience such as a speaker volume of a terminal device can be maximally improved while a voice coil temperature of the speaker is protected from being overloaded.