Type-C Audio Multiplexing Circuit With Discrete Switch Control
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Solution Overview
Problem
The high cost of integrated switches in mobile terminals due to their complex structure, which increases product costs and impairs compatibility with external devices.
Innovation Solution
A multiplexing circuit with three switch circuits (first, second, and third switch circuits) that enable or disable signal transmission based on voltage control, allowing for audio signal transmission to headsets or data transmission to external devices through a Type-C interface, using transistors, capacitors, and resistors to manage voltage and impedance effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an integrated switch is used to switch circuits coupled to an interface, then switching functionality is achieved, but product cost increases due to complex structure
Solution Approach 1:
The patent divides the integrated switch into multiple discrete transistors (first transistor for right audio channel, second transistor for left audio channel, third transistor for data transmission). Each transistor is independently controlled by voltage signals to achieve switching functionality without requiring a complex integrated switch component, thereby reducing product cost while maintaining interface compatibility.
2Adaptability or versatility
If an integrated switch is used to switch circuits coupled to an interface, then switching functionality is achieved, but product cost increases
Solution Approach 1:
The patent replaces the expensive integrated switch with multiple discrete transistors that can be manufactured separately and assembled. This segmentation allows for more flexible manufacturing processes and reduces dependency on costly integrated components, thereby lowering product cost while achieving the same switching functionality for interface compatibility.
Solution Approach 2:
The patent uses simple, discrete transistor components instead of complex integrated switches. These discrete transistors are cheaper individual components that can be easily replaced or manufactured, reducing overall product cost while maintaining the required switching functionality for different interface connections.
3Ease of manufacture
If discrete transistors are used instead of integrated switch, then product cost is reduced, but impedance changes and noise increase
Solution Approach 1:
The patent introduces constant voltage control circuits as intermediary components between the control signals and the transistors. These control circuits stabilize the gate voltage of each transistor, preventing impedance changes and reducing noise during switching operations. This intermediary mechanism ensures signal quality is maintained while using cost-effective discrete transistors.
Solution Approach 2:
The patent employs constant voltage control to dynamically adjust and stabilize the operating parameters (gate voltage) of the transistors. By maintaining constant voltage levels during switching, the impedance variations and noise generation are minimized, ensuring reliable signal transmission while using discrete, cost-effective transistor components.
Data Source
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AI summary
Embodiments of this application provide a multiplexing circuit and a mobile terminal, and relate to the field of electronic and communications technologies, to resolve a problem that product costs are high when a mobile phone uses an integrated switch. In the multiplexing circuit, a first switch circuit transmits, to a first signal transmission end, a right sound channel audio signal provided by a right sound channel transmission end. A second switch circuit transmits, to a second signal transmission end, a left sound channel audio signal provided by a left sound channel transmission end. Signal transmission between the first signal transmission end and a first output end and signal transmission between the second signal transmission end and a second output end are implemented by using a third switch circuit. The first switch circuit includes a first transistor and a first constant voltage control circuit. The first constant voltage control circuit loads the right sound channel audio signal to a gate electrode of the first transistor. The second switch circuit includes a second transistor and a second constant voltage control circuit. The second constant voltage control circuit loads the left sound channel audio signal to a gate electrode of the second transistor.