Amplifier Volume Gain Control for Loudspeaker Thermal Limits
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Solution Overview
Problem
Existing audio amplifier systems face challenges in limiting thermal power dissipation in loudspeakers without user-perceptible volume gain variations and avoiding surge phenomena, which can lead to coil destruction due to overheating.
Innovation Solution
A method that calculates a maximum volume gain based on the desired volume gain, effective intensity, and thermal characteristics of the loudspeaker, using an increasing monotonic function to adjust the applied volume gain, ensuring the image of the maximum desired volume gain is maintained while limiting thermal power dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If time constants are added to limit the speed of variation of desired volume gain, then thermal power is limited, but the device becomes difficult to adjust and surge phenomena occur
Solution Approach 1:
The patent changes the parameter of volume gain limitation from using fixed time constants to using a progressive limitation function with parameter α (alpha). This function adaptively limits the rate of change of applied volume gain based on the difference between desired and maximum permissible volume gain, eliminating the need for manual time constant adjustment while preventing surge phenomena.
2Reliability
If desired volume gain is automatically reduced to limit thermal power, then thermal power is limited, but the user perceives the variation
Solution Approach 1:
The patent applies a dynamic progressive limitation function that adaptively controls the reduction of applied volume gain. Instead of abrupt or linear reduction, the function progressively adjusts the applied volume gain based on the difference between desired and maximum permissible values, making the transition imperceptible to the user while effectively limiting thermal power.
3Reliability
If maximum volume gain is calculated based on thermal characteristics, then thermal power is limited, but pumping phenomena occur
Solution Approach 1:
The patent implements a feedback mechanism where the applied volume gain is continuously adjusted based on the difference between desired and maximum permissible volume gain. The progressive limitation function uses this feedback to smoothly constrain the applied gain within safe thermal limits, preventing the oscillations and pumping phenomena that occur with abrupt limitation methods.
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 effectively limits thermal power dissipation in loudspeakers without user-perceptible volume gain variations, preventing overheating and coil destruction while avoiding surge phenomena, ensuring stable and continuous sound reproduction.
Implementation Method 1
An electrodynamic loudspeaker is an electromechanical device whose purpose is to convert an electric voltage which is applied to its terminals into an acoustic pressure
Implementation Method 2
The loudspeaker has a certain capacity to dissipate in its environment, the thermal energy which it creates
Implementation Method 3
Due to the electrical resistance of the loudspeaker coil and the current flowing through it, thermal heating occurs
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a method for adapting the applied volume gain in an amplifier controlling at least one loudspeaker of an enclosure according to the desired volume gain selected by a user on a scale increased by a maximum desired volume gain, said method comprising steps of: determining (204) the effective intensity applied to at least one loudspeaker; calculating (206 and 208) a maximum volume gain from: the desired volume gain, the effective intensity applied to the loudspeaker, thermal characteristics of the loudspeaker, and the maximum desired volume gain; calculating (210) an increasing monotonic function providing an applied volume gain variable according to the desired volume gain such that the image of the maximum desired volume gain by the monotonic function is equal to the maximum volume gain; and applying (212), to the amplifier, as an applied volume gain, the minimum of the maximum volume gain and the applied volume gain which is variable for the desired volume gain.