Audio Volume Circuit Abnormal-State Detection via Output Comparison
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Solution Overview
Problem
Existing electronic volume devices face challenges in detecting abnormal states in circuits, particularly due to DC offsets in power amplifiers, which can lead to reduced reliability and require complex feedback control systems.
Innovation Solution
An electronic volume device comprising an amplifier, comparator, and detection terminal that compares the output audio signal with a reference signal, using a logical detection signal to determine abnormal states without feedback control, and optionally includes a phase adjustment unit and mixer to ensure accurate level detection, with the ability to be monolithically integrated on a semiconductor substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the input level of the power amplifier is detected using AD conversion and lookup table as in Patent document 3, then the threshold value can be determined, but the circuit scale is enlarged
Solution Approach 1:
The invention extracts only the essential function of threshold determination from the complex AD conversion and lookup table system. By using a comparator that directly compares the input signal with a reference voltage, the patent eliminates the need for AD conversion circuits and memory storage, achieving threshold determination with minimal circuit components.
Solution Approach 2:
The patent replaces expensive and complex AD conversion hardware with a simple comparator circuit that uses basic electronic components. This substitution achieves the same functional goal (threshold determination) with significantly reduced circuit complexity and lower component cost.
2Measurement precision
If feedback control operation is used to detect abnormal states, then detection accuracy can be improved, but the system complexity increases
Solution Approach 1:
The invention performs preliminary action by determining the threshold value in advance based on the input signal level during normal operation. This pre-determined threshold is then used for abnormal state detection without requiring complex real-time feedback control, simplifying the detection system while maintaining accuracy.
Solution Approach 2:
The patent introduces a detection signal as an intermediary that carries abnormal state information from the power amplifier to the external system. This detection signal, generated by the simple comparator circuit, replaces the need for complex feedback control mechanisms while effectively transmitting detection results.
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
Enables simple detection of abnormal states in the circuit during playback operations, preventing potential issues like DC offsets without the need for complex feedback systems, ensuring reliable audio output and reducing circuit complexity.
Implementation Method 1
a comparator which compares the second audio signal output from the amplifier with a reference signal
Data Source
AI summary
Amplifiers amplify input first audio signals according to volume values set beforehand. Via output terminals, the amplifiers output second audio signals to externally connected power amplifiers. A comparison unit compares the second audio signals with a reference signal. Via the detection terminals, detection signals are output externally according to the comparison results obtained by the comparison unit.