Capacitance Coupling Charging Circuit Blocks DC Fault Current
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Solution Overview
Problem
Conventional mobile terminal charging circuits face reliability issues due to the risk of MOS transistor breakdown, leading to overcurrent and improper charging, which can cause battery failure, and increasing on-resistance to prevent burnout results in heat accumulation and low power efficiency.
Innovation Solution
A charging circuit that includes a capacitance coupling component between the charging port and the battery, which blocks direct current (DC) power when the first circuit malfunctions, ensuring only alternating current (AC) power is transmitted to the battery, thereby enhancing stability and preventing direct current from flowing to the battery in fault states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the on-resistance of the MOS transistor is increased to improve breakdown threshold voltage, then the reliability of the charging circuit is improved, but heat accumulation increases and power transmission efficiency decreases
Solution Approach 1:
A capacitance coupling component is introduced as an intermediary between the MOS transistor and the battery. This capacitor blocks DC current while allowing AC current to pass through, enabling the MOS transistor to operate with low on-resistance for high efficiency while preventing DC overcurrent from reaching the battery, thus resolving the contradiction between reliability and power efficiency
2Reliability
If the on-resistance of the MOS transistor is increased to prevent burnout, then the reliability is improved, but heat accumulation occurs
Solution Approach 1:
The capacitance coupling component serves as a protective intermediary that blocks DC current paths. This allows the MOS transistor to maintain low on-resistance and operate efficiently without excessive heat generation, while the capacitor prevents DC overcurrent conditions that would cause burnout, thus resolving the contradiction between burnout prevention and heat accumulation
3Reliability
If a capacitance coupling component is introduced to block DC current, then the reliability and safety are improved, but the device complexity increases
Solution Approach 1:
A capacitance coupling component is introduced as an intermediary between the MOS transistor and the battery. This capacitor blocks DC current while allowing AC current to pass through, enabling the MOS transistor to operate with low on-resistance for high efficiency while preventing DC overcurrent from reaching the battery, thus resolving the contradiction between reliability and power efficiency
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 enhances the reliability and safety of the charging circuit by preventing direct current from reaching the battery during faults, reducing the risk of damage and overheating, while maintaining high power transmission efficiency with low on-resistance MOSFETs.
Implementation Method 1
a capacitance coupling component, coupled between the first circuit and the second circuit, being configured to pass the alternating current (AC) power signal from the first circuit to the second circuit when the first circuit works normally but block the direct current (DC) power signal flowing through the charging circuit when the first circuit fails to generate alternating current (AC) power signal due to malfunction of the first circuit
Implementation Method 2
a first circuit, coupled to the charging port, being configured to draw direct current (DC) power signal from an electrical power source through the charging port, and being configured to convert the direct current (DC) power signal flowing through the charging port to alternating current (AC) power signal
Data Source
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AI summary
The present disclosure proposes a charging circuit and a mobile terminal. The charging circuit includes: a first circuit, coupled to a charging port, to draw DC power signal, and convert the DC power signal into AC power signal; a second circuit, coupled to the battery, configured to receive the AC power signal from the first circuit, and convert the AC power signal into DC power signal for charging the battery; a capacitance coupling component, coupled between the first circuit and the second circuit. The capacitance coupling component is configured to block DC power signal from the first circuit. That is, the DC power signal fails to pass through the first circuit. Thus, the DC power signal flowing through the charging port does not flow to the second circuit and the battery directly when the first circuit malfunctions. Accordingly, the stability of the charging circuit is enhanced.