Vehicle Speaker Failure Detection via Phase Difference Analysis
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Solution Overview
Problem
Existing vehicle speaker failure detection devices are cumbersome, costly, and unable to detect open-circuits during normal operation, due to complex circuitry and the need for multiple components.
Innovation Solution
A failure detection device for vehicle speakers that includes a signal generator, amplifier, coupling capacitor, detection circuit, and determination section, which detects open-circuits by analyzing the phase difference between the sound signal and terminal voltage, allowing for continuous operation monitoring and reduced component count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional error determination circuits with current and voltage transformers are used, then open-circuit detection is achieved, but the number of parts, size, and cost increase
Solution Approach 1:
The patent extracts the detection function from separate current and voltage transformers and integrates it into the existing amplifier circuit. The amplifier's output terminal directly provides both the drive signal and the detection signal, eliminating the need for additional transformation components while maintaining detection capability.
Solution Approach 2:
The amplifier circuit is given dual functionality: it serves both as the power amplification device for the speaker and as the detection circuit for open-circuit detection. The same output terminal and internal circuitry are used for both driving the speaker and detecting faults, reducing overall system complexity.
2Measurement precision
If equivalent circuits and switch circuits are added for open-circuit detection, then detection accuracy improves, but device complexity and cost increase
Solution Approach 1:
The amplifier circuit performs self-detection by monitoring its own output terminal voltage. The detection function is embedded within the amplifier's existing structure, allowing it to detect open-circuits without requiring external equivalent circuits or additional switch circuits.
3Use of energy by moving object
If detection voltage is supplied only during detection mode, then power consumption is reduced, but continuous monitoring during normal operation is not achieved
Solution Approach 1:
The detection of terminal voltage occurs continuously during normal amplifier operation without requiring a separate detection mode. The amplifier constantly monitors its output terminal voltage while driving the speaker, enabling real-time fault detection without interrupting or separating the detection function from normal operation.
4Adaptability or versatility
If multiple separate detection circuits are used for different failure types, then detection comprehensiveness improves, but device complexity increases
Solution Approach 1:
A single terminal voltage detection mechanism covers multiple failure modes including open-circuits, short-circuits, and abnormal impedance conditions. The determination section analyzes the detected voltage to identify different fault types, providing comprehensive detection coverage through one unified detection circuit.
Data Source
AI summary
A failure detection device for a vehicle speaker includes a signal generator, an amplifier, a coupling capacitor, a detection circuit, and a determination section. The signal generator generates a sound signal corresponding to a sound outputted from the speaker. The amplifier amplifies the sound signal generated by the signal generator. The coupling capacitor supplies the sound signal amplified by the amplifier to the speaker. The detection circuit directly or indirectly detects a terminal voltage on a terminal of the speaker. The determination section determines whether an open-circuit occurs in the speaker based on a phase difference between a phase of the sound signal and a phase of the terminal voltage. The terminal of the speaker is coupled to the coupling capacitor.