Audio Amplifier Supply Feedback to Prevent Playback Whistling
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Solution Overview
Problem
Class D audio power amplifiers in audio playback systems experience fluctuations in output power due to lack of an independently regulatable power supply, leading to howling and popping noises during audio playback.
Innovation Solution
An audio processing circuit with a feedback control circuit that regulates the supply voltage to the audio amplifier based on the amplitude of the audio signal, using a feedback control circuit and power supply circuit to stabilize the voltage and prevent fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a class D audio power amplifier is used to drive the audio playback assembly, then the size is reduced and power is increased, but the audio quality deteriorates due to susceptibility to potential fluctuations and lack of independently regulatable power supply
Solution Approach 1:
The power supply system is segmented into a main power supply and a dedicated auxiliary power supply specifically for the audio amplifier. This separation allows the auxiliary power supply to be independently regulated, providing stable voltage to the audio amplifier while maintaining the compact size and high power benefits of the class D amplifier architecture.
Solution Approach 2:
A feedback control circuit is implemented that detects the audio signal amplitude and dynamically adjusts the auxiliary power supply output voltage accordingly. The feedback control circuit receives the audio signal from the audio amplifier, determines its amplitude, and generates a control signal to regulate the auxiliary power supply, ensuring the supply voltage matches the actual power consumption needs and remains stable during playback.
2Power
If the power supply voltage is increased to meet high power demands, then the power output is improved, but the stability deteriorates due to potential fluctuations causing howling and popping noises
Solution Approach 1:
The auxiliary power supply is designed with dynamic voltage regulation capability, allowing it to adjust its output voltage in real-time based on the audio signal amplitude. During high-volume playback, the supply voltage increases to meet power demands, while during low-volume playback, the voltage decreases to reduce fluctuations. This dynamic adaptation eliminates the trade-off between power output and voltage stability.
Solution Approach 2:
The system changes the supply voltage parameter dynamically rather than maintaining a fixed high voltage. The auxiliary power supply adjusts its output voltage according to the audio signal amplitude, ensuring optimal voltage levels for different playback scenarios. This parameter change strategy prevents potential fluctuations and associated noises while maintaining sufficient power output when needed.
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
The solution effectively prevents howling and popping noises by maintaining stable supply voltage, thereby improving audio playback quality.
Implementation Method 1
the feedback control circuit is configured to control, based on an audio signal received at the input terminal of the audio amplifier, the power supply circuit to regulate a supply voltage provided to the power terminal of the audio amplifier
Data Source
AI summary
Provided are an audio playing module and an audio processing circuit thereof, and an electronic device, which belong to the technical field of electronics. In the audio processing circuit, by adding a feedback control circuit between a power circuit and an audio amplifier, the feedback control circuit can control, according to a change in the amplitude of an audio signal received by the audio amplifier, the power circuit to adjust a power supply voltage provided for the audio amplifier. Thus, when the amplitude of the audio signal changes, an appropriate power supply voltage can be matched for the audio amplifier by means of the feedback control circuit, thereby solving the problem of the audio playing module generating whistling when the amplitude of the audio signal changes, and thus optimizing the sound quality of played sounds.