Earphone Socket Switch Circuit for Noise Reduction
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Solution Overview
Problem
Noise is generated when earphones are plugged into or unplugged from a socket due to voltage loops in the audio channels, particularly in active noise reduction earphones, impairing user experience.
Innovation Solution
A terminal system with a switch circuit and bleeder circuit is introduced, which disconnects the power supply to the earphone socket's second pin when certain voltage conditions are met, preventing voltage loops and noise in the audio channels by adjusting the connection based on detected voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If power is supplied to the earphone through pin 2 for active noise reduction function, then the earphone can provide active noise reduction capability, but noise is generated during plugging and unplugging due to voltage loops in the audio channels
Solution Approach 1:
The patent applies preliminary action by detecting the insertion state of the earphone beforehand and pre-controlling the switch circuit to establish or disconnect the power supply path. When the earphone is detected to be inserted, the switch circuit is controlled to connect pin 2 to the power supply circuit, enabling power supply before audio signal transmission begins. This preliminary establishment of proper electrical connections prevents voltage loops and noise generation during the plugging process.
Solution Approach 2:
The patent implements dynamics by using a controllable switch circuit that dynamically changes the connection state between pin 2 and the power supply circuit based on real-time detection of earphone insertion status. The switch circuit transitions between connected and disconnected states, allowing the system to adaptively manage power supply to avoid noise during plugging/unplugging while maintaining it during normal operation. This dynamic control enables the system to optimize both noise reduction capability and power supply efficiency.
2Adaptability or versatility
If the earphone socket follows standard pin configuration, then compatibility with standard earphones is maintained, but voltage loops form between pin 2 (power) and pin 3 (audio right channel) causing noise
Solution Approach 1:
The patent applies segmentation by separating the power supply function (pin 2) from the audio signal transmission function (pin 3) through a controllable switch circuit. Instead of having a fixed direct connection between pin 2 and the power supply, the switch circuit creates an independent controllable path. This segmentation allows the system to maintain standard pin configuration for compatibility while preventing unwanted electrical connections that cause voltage loops and noise between power and audio channels.
3Power
If supply voltage is increased to improve active noise reduction performance, then noise reduction capability is enhanced, but noise during plugging and unplugging becomes louder
Solution Approach 1:
The patent applies preliminary action by detecting the earphone insertion state in advance and controlling the switch circuit to establish the power supply path before high-voltage power is applied. When insertion is detected, the switch connects pin 2 to the power supply circuit, allowing controlled voltage application. This preliminary establishment of the proper electrical path ensures that high supply voltage is only applied when the earphone is properly connected, preventing high-voltage-induced noise during plugging/unplugging while enabling enhanced active noise reduction performance during normal operation.
Data Source
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AI summary
Embodiments of the present invention provide a terminal and a system capable of reducing noise generated in a process of plugging or unplugging an earphone. The terminal includes: an earphone socket, a switch circuit, an earphone power supply circuit, and a bleeder circuit, where a first pin of the earphone socket is connected to a control pin of the switch circuit, a second pin of the earphone socket is connected to an input terminal of the switch circuit, a first output terminal of the switch circuit is connected to the earphone power supply circuit, and a second output terminal of the switch circuit is connected to the bleeder circuit; when an input voltage of the control pin of the switch circuit is higher than a second preset voltage value, the control pin of the switch circuit controls the input terminal of the switch circuit to be connected to the second output terminal of the switch circuit. According to the embodiments of the present invention, the switch circuit is added into the terminal, and when the input voltage of the control pin of the switch circuit is higher than the second preset voltage value, a connection between the earphone power supply circuit and the second pin of the earphone socket is disconnected. Therefore, a voltage on the earphone power supply circuit does not form a loop on an audio-left channel or an audio-right channel of the earphone, so that noise generated when the earphone is being plugged into or unplugged from the earphone socket is effectively reduced.