Capacitive Coupling Charging Circuit DC Path Isolation
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Solution Overview
Problem
The reliability of charging circuits in mobile terminals is compromised due to the risk of MOS transistor breakdown, which can lead to excessive battery voltage and other serious issues, and existing solutions either increase on-resistance, reducing efficiency or fail to prevent direct DC current flow to the battery upon transistor failure.
Innovation Solution
A capacitive coupling element is introduced to separate the DC path in the charging circuit, disconnecting the DC current flow to the battery upon failure of the first circuit, thereby improving reliability and allowing for lower on-resistance MOS transistors, enhancing energy transfer efficiency and reducing heating and loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the on-resistance of the MOS transistor is increased to improve voltage resistance, then the reliability of the MOS transistor is improved, but the charging circuit becomes prone to overheating and energy transmission efficiency decreases
Solution Approach 1:
The patent introduces a protection circuit as an intermediary between the MOS transistor and the battery. This protection circuit includes current detection components and control mechanisms that monitor and limit the current flow, preventing direct current flow to the battery upon transistor failure while allowing efficient operation during normal conditions.
2Reliability
If the on-resistance of the MOS transistor is increased to improve voltage resistance, then the reliability of the charging circuit is improved, but the charging circuit becomes prone to overheating
Solution Approach 1:
The protection circuit acts as an intermediary that prevents direct current flow to the battery upon transistor failure, thereby improving reliability without requiring increased on-resistance. By using current detection and control mechanisms, the system can maintain low on-resistance for efficient power transfer while preventing overheating through active current management.
3Reliability
If a protection circuit is added to prevent direct current flow to the battery upon transistor failure, then the reliability of the charging circuit is improved, but the device complexity increases
Solution Approach 1:
The protection circuit is designed as a relatively simple intermediary system that can be integrated into the existing charging circuit. It includes current detection components and control mechanisms that monitor the current flow and activate protection only when needed, thereby improving reliability while minimizing the increase in device complexity.
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
This solution effectively prevents direct DC current flow to the battery during MOS transistor failure, improving charging circuit reliability and maintaining energy transfer efficiency, even during quick charging modes.
Implementation Method 1
a capacitive coupling element (33) disconnects a DC path of the charging circuit (30)
Data Source
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AI summary
It is provided a charging circuit and a mobile terminal. The charging circuit is arranged between a charging interface and a battery of the mobile terminal. The charging circuit comprises a first circuit, a capacitive coupling element, and a second circuit connected in series successively between the charging interface and the battery. The capacitive coupling element disconnects a direct-current (DC) path of the charging circuit. According to embodiments of the present disclosure, a DC path of the charging circuit is separated by the capacitive coupling element. That is to say, there is no DC path in the charging circuit. DC current from the charging interface would not be output directly to the second circuit and the battery upon failure of the first circuit, whereby reliability of the charging circuit is improved.