Audio Signal Clipping Control for Overcurrent Speaker Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electronic devices face issues with sudden shutdown due to overcurrent protection circuits, leading to interruptions in output sound and potential speaker damage from large current flows, without effectively balancing sound quality and protection.
Innovation Solution
Implementing a current detection circuit and processor that clip the signal when a threshold is exceeded for a specific time, preventing the overcurrent protection circuit from activating and maintaining sound quality by clipping the musical sound signal only when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the overcurrent protection circuit stops power supply when a large current is detected, then the speaker is protected from breakage, but the output sound is interrupted and the electronic device shuts down unexpectedly
Solution Approach 1:
The patent divides the protection function into two separate components: a clipper circuit that clips the audio signal to prevent excessive current, and an overcurrent protection circuit that would otherwise stop power supply. This segmentation allows the clipper to handle transient peaks without triggering the overcurrent protection, maintaining output continuity while still protecting the speaker.
Solution Approach 2:
The clipper circuit performs preliminary action by clipping the audio signal before it reaches the amplifier and power supply. By preemptively limiting the signal amplitude, the clipper prevents the conditions that would trigger the overcurrent protection circuit, thereby avoiding unexpected shutdowns while maintaining speaker protection.
2Reliability
If the clipper activates frequently to protect against large currents, then the speaker is protected, but the sound quality deteriorates due to frequent clipping
Solution Approach 1:
The patent employs a threshold-based feedback mechanism where the clipper activates only when the signal exceeds a predetermined threshold level. This feedback control ensures that clipping occurs only when necessary for protection, rather than continuously, thereby maintaining sound quality while still protecting the speaker from damage.
Solution Approach 2:
The clipper changes the parameter of signal amplitude selectively by applying clipping only when the signal exceeds the threshold. This parameter-based approach allows the system to maintain the original signal characteristics (and thus sound quality) during normal operation while introducing amplitude limitation only when protection is needed.
3Productivity
If the overcurrent protection circuit is removed to maintain continuous output sound, then the sound continuity is improved, but the speaker becomes vulnerable to breakage from large currents
Solution Approach 1:
The clipper circuit acts as an intermediary between the audio signal source and the amplifier/power supply. It mediates the signal by clipping excessive amplitudes before they can cause harmful current flows, thereby protecting the speaker without interrupting the overall power supply and maintaining output sound continuity.
Solution Approach 2:
The patent replaces the mechanical/power-based protection mechanism (overcurrent protection circuit that stops power supply) with a signal-processing-based mechanism (clipper that modifies the audio signal). This substitution allows protection to be achieved through signal manipulation rather than power interruption, maintaining output continuity while protecting the speaker.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An electronic device includes: a current detection circuit (10, 20) that detects a current supplied from an adapter; and a processor (30) that processes a signal. The processor (30): clips the signal (S110) in a case where the current equal to or larger than a first threshold from the current detection circuit (10, 20) is continuously detected for a first time (S109: Yes), and outputs a clipped clip signal (I2S).