Power Supply Circuit for Adaptive Full-Charge Detection

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Solution Overview

Problem

Existing battery charging methods fail to accurately determine full charge capacity when using low-rated power adapters, leading to reduced charge capacity due to reliance on fixed taper voltages that do not account for individual circuit resistance variations, resulting in insufficient charging even when voltage and current conditions are met.

Innovation Solution

A power supply circuit that dynamically adjusts detection voltages based on measured circuit resistance and actual charging conditions, switching to a second detection voltage when necessary to ensure accurate full charge determination, even during system operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a fixed taper voltage is used for full charge determination, then the charging control is simple, but the battery charge capacity becomes insufficient when circuit resistance varies

Engineering Contradiction:
Improvecharging control complexityVSAvoidbattery charge capacity
Core Design Contradiction:
Device complexityVSQuantity of substance

Solution Approach 1:

The patent applies dynamics by switching from a fixed taper voltage to a dynamic detection voltage that adapts to individual circuit resistance values. The detection voltage is calculated based on measured circuit resistance, allowing the charging system to adjust the full charge determination threshold according to actual circuit conditions, thereby resolving the contradiction between control simplicity and charging accuracy.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of detection voltage from a fixed value to a variable value determined by circuit resistance measurements. By calculating the detection voltage as (charging voltage - (circuit resistance × detection current)), the system adapts the voltage threshold to match actual circuit characteristics, ensuring accurate full charge detection while maintaining reasonable control complexity.

Inventive Principle:
Principle #35Parameter changes

2Weight of moving object

If a low-rated power adapter is used, then the device portability is improved, but the battery charging power becomes insufficient

Engineering Contradiction:
Improvedevice portabilityVSAvoidbattery charging power
Core Design Contradiction:
Weight of moving objectVSPower

Solution Approach 1:

The patent implements feedback by measuring the actual circuit resistance during charging and using this information to adjust the detection voltage dynamically. This feedback mechanism allows the system to maximize battery charging efficiency by accurately determining full charge conditions, thereby optimizing the limited charging power available from low-rated adapters and ensuring complete charging despite power constraints.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the detection voltage parameter based on measured circuit resistance to optimize charging efficiency. By adapting the detection voltage to actual circuit conditions, the system extracts maximum charging capacity from limited adapter power, resolving the contradiction between portability and charging power sufficiency.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the detection voltage is set lower to account for circuit resistance, then the full charge determination becomes safer, but the battery is undercharged

Engineering Contradiction:
Improvefull charge determination accuracyVSAvoidbattery charge capacity
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent dynamically adjusts the detection voltage parameter based on measured circuit resistance values. Instead of using a fixed conservative voltage threshold, the system calculates an appropriate detection voltage that accounts for actual circuit losses, thereby achieving both reliable full charge determination and complete battery charging capacity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system performs self-characterization by measuring its own circuit resistance and using this information to optimize the detection voltage. This self-service approach allows the charging system to adapt to its specific hardware characteristics, ensuring both safety and complete charging without manual intervention or overly conservative thresholds.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4472017B1Power supply circuit, electronic apparatus, and control method
Publication Date: 2026.03.25 LENOVO (BEIJING) LTD
  • EP4472017B1 patent drawingFigure 1
  • EP4472017B1 patent drawingFigure 2
  • EP4472017B1 patent drawingFigure 3~4

AI summary

The present application is to finish charging more accurately in the fully charged state even when electric power is consumed in a system. A power supply circuit supplies, to the system, system power required for the system out of DC power supplied from a power supply, and charges a battery with charging power as the remaining power, and when a cell voltage of the battery is a predetermined detection voltage or more and a charging current of the charging power becomes a predetermined detection current or less, the power supply circuit determines that the battery charged state is fully charged, estimates, as a second detection voltage, the cell voltage at the time when determining that the charged state is fully charged based on the cell voltage obtained in a specific charging state to the battery, and updates the predetermined detection voltage from a predetermined first detection voltage to the second detection voltage.