Earphone Jack Microphone Terminal Noise Suppression
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Solution Overview
Problem
Conventional earphone devices experience annoying tick or click noises when being removed from mobile terminal earphone connection interfaces due to residual bias voltage, causing user inconvenience.
Innovation Solution
An earphone connection interface design featuring a switch element that connects a capacitor to the microphone terminal when the earphone is inserted and disconnects it to ground when removed, preventing noise induction by converting the microphone terminal's potential to a ground potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If bias voltage is supplied to the microphone terminal to support microphone operation, then microphone function is enabled, but tick noise is induced when earphone is removed
Solution Approach 1:
The patent applies preliminary action by disconnecting the bias voltage from the microphone terminal before the earphone plug is fully removed. The controller detects the removal state and proactively cuts off the bias voltage supply, preventing the tick noise that would otherwise occur when the plug contacts the microphone terminal during removal. This resolves the contradiction by enabling microphone function during insertion while preventing noise during removal.
2Duration of action of stationary object
If bias voltage is maintained during earphone removal, then microphone terminal remains powered, but noise is induced to earphone terminals
Solution Approach 1:
The patent applies dynamics by making the bias voltage supply dynamic rather than static. The controller dynamically adjusts the bias voltage supply state based on the earphone insertion/removal detection. When inserted, the bias voltage is supplied to power the microphone terminal; when removal is detected, the supply is cut off. This dynamic control resolves the contradiction between maintaining power supply duration and preventing noise induction.
3Reliability
If earphone plug terminals contact microphone terminal during removal, then electrical connection is maintained, but tick noise occurs in output
Solution Approach 1:
The patent applies preliminary anti-action by taking countermeasures before the harmful effect occurs. When the controller detects that the earphone plug is being removed, it proactively disconnects the bias voltage from the microphone terminal, creating a protective action that prevents the tick noise from occurring when the plug terminals contact the microphone terminal during removal. This resolves the contradiction by maintaining connection reliability while preventing noise through preemptive voltage cutoff.
Data Source
AI summary
An earphone connection interface, a terminal including the same, and a method of operating the terminal are provided. The earphone connection interface includes: a terminal left terminal, a terminal right terminal, a terminal ground terminal, an earphone detection terminal, and a terminal microphone terminal disposed sequentially along an inner wall of a cylindrical groove and an ear microphone bias voltage source electrically connected to the terminal microphone terminal; and a capacitor electrically connected to the terminal microphone terminal through a switch element.