Wireless Headset Charging Circuit Switching for Lower Impedance

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Solution Overview

Problem

Existing charging cases have high total impedance in their charging circuits, leading to poor charging efficiency for wireless headsets.

Innovation Solution

A dual charging circuit system is implemented, where a first charging circuit with lower maximum voltage and higher impedance is switched to a second charging circuit with higher maximum voltage and lower impedance based on voltage differences, using a transfer switch controlled by a controller to optimize charging efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a single charging circuit with high maximum voltage is used, then charging speed is improved, but total impedance increases and charging efficiency deteriorates

Engineering Contradiction:
Improvecharging speedVSAvoidcharging efficiency
Core Design Contradiction:
SpeedVSLoss of energy

Solution Approach 1:

The charging circuit is segmented into two distinct circuits: a first charging circuit with lower maximum voltage (5V) and higher impedance, and a second charging circuit with higher maximum voltage (12V) and lower impedance. The transfer switch enables selective switching between these two segmented circuits based on charging requirements, allowing the system to optimize between charging speed and efficiency by choosing the appropriate circuit for each charging phase.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If a single charging circuit is used, then device complexity is reduced, but adaptability to different charging phases deteriorates

Engineering Contradiction:
Improvecharging circuit complexityVSAvoidadaptability to charging phases
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The charging circuit incorporates a transfer switch that dynamically switches between the first and second charging circuits based on real-time voltage difference detection. This dynamic adaptability allows the system to adjust its charging characteristics according to different charging phases (pre-charging vs. fast charging), improving versatility while maintaining manageable complexity through automated control.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes key electrical parameters by switching between two distinct charging circuits with different voltage and impedance characteristics. The first circuit operates at lower voltage (5V) with higher impedance for pre-charging, while the second circuit operates at higher voltage (12V) with lower impedance for fast charging. This parameter change strategy enables the system to adapt to different charging phases without requiring a completely different circuit design.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If high impedance charging circuit is used, then safety and protection are improved, but charging efficiency deteriorates

Engineering Contradiction:
Improvecharging safetyVSAvoidcharging efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The charging system is segmented into two circuits with different impedance characteristics. The first charging circuit with higher impedance provides enhanced safety and protection during pre-charging phases, while the second charging circuit with lower impedance delivers higher charging efficiency during fast charging phases. This segmentation allows the system to prioritize safety when needed and efficiency when appropriate.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The transfer switch enables dynamic switching between the high-impedance first charging circuit and the low-impedance second charging circuit based on real-time voltage difference detection. During pre-charging when safety is paramount, the high-impedance circuit is used. When the voltage difference exceeds the threshold and fast charging is appropriate, the system dynamically switches to the low-impedance circuit for improved efficiency.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4297239A1Method for charging wireless headset, charging circuit and charging case
Publication Date: 2023.12.27 BEIJING XIAOMI MOBILE SOFTWARE CO LTD
  • EP4297239A1 patent drawingFigure 1~3
  • EP4297239A1 patent drawingFigure 4
  • EP4297239A1 patent drawing

AI summary

A charging circuit is disclosed, which relates to the field of charging technologies. The charging circuit includes a protection circuit (12) and a charging control switch (13) connected in series, and a transfer switch (112). The transfer switch (112) is configured to switch to a first charging circuit by connecting to the protection circuit (12), and switch to a second charging circuit by connecting to the charging control switch (13). A maximum charging voltage of the first charging circuit is lower than a maximum charging voltage of the second charging circuit. The invention may enable the battery to be charged by two charging circuits, in which the second charging circuit has a larger maximum charging voltage and a smaller impedance than the first charging circuit, thus improving the charging efficiency.