Type-C Earphone Pull-Up Circuit for Pop-Free Insertion Detection
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Solution Overview
Problem
Electronic devices with USB Type-C interfaces struggle to differentiate between normal and reverse insertion of earphones, leading to POP sounds and functional issues such as impaired audio and button functionality.
Innovation Solution
An electronic device with a controller and pull-up circuit connected to the Type-C interface, which adjusts resistance values to identify earphone insertion type by controlling the pull-up circuit's access resistance to different values during and after insertion, disconnecting the audio path during identification to suppress POP sounds without altering the original identification logic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the left and right channels of the earphone are disconnected to eliminate the POP sound, then the POP sound is suppressed, but the electronic device cannot normally recognize normal/reverse insertion of the earphone
Solution Approach 1:
The patent segments the identification process into two distinct phases: a first identification phase using a first identification method that does not require audio path connection, and a second identification phase using a second identification method that requires audio path connection. This allows the system to perform insertion detection without being blocked by the POP sound issue, while still maintaining the ability to recognize insertion direction when audio paths are connected.
Solution Approach 2:
The patent applies preliminary action by performing the first identification phase before establishing the audio path connection. The controller performs preliminary identification using the first identification method (which does not depend on audio path connection status) before the audio path is fully established, allowing insertion recognition to occur even when the audio path is disconnected to prevent POP sounds.
2Object-affected harmful factors
If the audio path is disconnected to suppress POP sound, then the harmful sound is eliminated, but button functionality becomes abnormal
Solution Approach 1:
The patent segments the identification methods into two independent approaches: the first identification method that works regardless of audio path connection status, and the second identification method that requires audio path connection. This segmentation allows the system to maintain button functionality through the first identification method while suppressing POP sounds by disconnecting the audio path during the second identification phase.
Solution Approach 2:
The patent uses the pull-up circuit as an intermediary component that enables the first identification method to function independently of the audio path connection status. The pull-up circuit provides the necessary electrical path for detection without requiring the audio path to be connected, thus serving as a mediator that allows insertion recognition to proceed even when the audio path is disconnected for POP sound suppression.
3Measurement precision
If the pull-up circuit access resistance is adjusted to enable identification, then insertion recognition is improved, but the original identification logic may be altered
Solution Approach 1:
The patent segments the identification logic into two independent methods with different requirements. The first identification method uses the pull-up circuit with adjusted access resistance and does not require audio path connection, while the second identification method uses the original logic and requires audio path connection. This segmentation allows the system to maintain both simple and complex identification approaches without interfering with each other.
Solution Approach 2:
The patent applies dynamics by making the pull-up circuit access resistance adjustable rather than fixed. The controller can dynamically change the access resistance value of the pull-up circuit based on the identification phase, allowing the system to optimize for different identification methods without permanently altering the original identification logic.
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
Effectively identifies normal/reverse earphone insertion, suppresses POP sounds, and maintains original button functionality by adjusting resistance values in the pull-up circuit, ensuring accurate identification and normal operation.
Implementation Method 1
The controller is configured to control an access resistance value of the pull-up circuit to be a first resistance value, and identify normal/reverse insertion of the earphone based on a voltage at the MIC pin of the Type-C interface
Data Source
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AI summary
This application relates to the technical field of circuits, and provides an electronic device, a pull-up circuit, and a method for suppressing a POP sound of an earphone. The electronic device includes a controller, a pull-up circuit, and a Type-C interface. An output terminal of the pull-up circuit is configured to be connected to a Type-C plug of the earphone through a MIC pin of the Type-C interface. The controller is configured to control the electronic device to be disconnected from an audio path of the earphone, control an access resistance value of the pull-up circuit to be a first resistance value, and identify normal/reverse insertion of the earphone based on a voltage of the MIC pin of the Type-C interface when the earphone is inserted into the Type-C interface of the electronic device through the Type-C plug. The controller is further configured to control the access resistance value of the pull-up circuit to be a second resistance value after the identification is completed, and the first resistance value is greater than the second resistance value. In this way, the electronic device can normally identify normal/reverse insertion of the earphone while eliminating the POP sound when the earphone is reversely inserted.