Charging Circuit Voltage Stabilization Without Adapter Capacitors

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Solution Overview

Problem

Existing charging architectures in terminal devices face challenges with miniaturization due to the use of electrolytic capacitors, which are bulky and limit voltage stability, and current solutions that rely on battery voltage for stability are inflexible.

Innovation Solution

A charging circuit with a conversion circuit and controller that modulates direct current voltage based on a threshold, allowing it to switch directions between the adapter and terminal battery to maintain stable charging, even with pulsating input voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If an electrolytic capacitor is disposed in the terminal adapter to stabilize output voltage, then voltage stability is improved, but adapter volume increases

Engineering Contradiction:
Improveoutput voltage stabilityVSAvoidadapter volume
Core Design Contradiction:
Stability of the object's compositionVSVolume of stationary object

Solution Approach 1:

The patent removes the electrolytic capacitor from the adapter, extracting the volume-consuming component while addressing voltage stability through an alternative architecture where the terminal battery serves as the energy storage element, enabling adapter miniaturization

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a control circuit as an intermediary between the adapter and terminal battery, which actively regulates voltage by controlling charging current based on detected voltage levels, compensating for the removed capacitor's function without requiring its physical presence

Inventive Principle:
Principle #24Intermediary (Mediator)

2Volume of stationary object

If the electrolytic capacitor is removed to achieve miniaturization, then adapter volume decreases, but output voltage fluctuates

Engineering Contradiction:
Improveadapter volumeVSAvoidoutput voltage stability
Core Design Contradiction:
Volume of stationary objectVSStability of the object's composition

Solution Approach 1:

The patent implements a feedback control mechanism where the control circuit continuously detects the adapter's output voltage and adjusts the charging current accordingly, increasing current when voltage is high and decreasing it when voltage is low, thereby stabilizing output voltage without requiring a capacitor

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The terminal battery serves dual purposes: as the energy storage device being charged and as an active participant in voltage stabilization through the feedback control mechanism, where its voltage characteristics help clamp and stabilize the adapter's output voltage

Inventive Principle:
Principle #25Self-service

3Stability of the object's composition

If the adapter directly charges the terminal battery to stabilize output voltage near battery voltage, then voltage stability is improved, but voltage adjustment flexibility is reduced

Engineering Contradiction:
Improveoutput voltage stabilityVSAvoidvoltage adjustment flexibility
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent creates a dynamic charging architecture where the control circuit can flexibly adjust charging parameters based on real-time voltage detection, allowing the system to adapt between different charging modes (standard charging, fast charging, voltage clamping) rather than being fixed to a single direct-charging mode

Inventive Principle:
Principle #15Dynamics

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

Enables miniaturization of adapters by removing electrolytic capacitors while ensuring continuous charging by stabilizing voltage and preventing protection mechanism triggers.

Implementation Method 1

the controller is configured to modulate a voltage of the first direct current to a charging voltage to charge the terminal battery

Methodology Applied
Scientific EffectVoltage modulation:

Implementation Method 2

when a voltage of the charging interface is less than a threshold voltage, the conversion circuit is configured to transmit a second direct current from the terminal battery to the charging interface

Methodology Applied
Scientific EffectBattery discharge: Battery (electricity)

Data Source

PatentEP4191816B1Charging circuit, terminal device, charging system and charging method
Publication Date: 2025.10.08 HUAWEI DIGITAL POWER TECH CO LTD
  • EP4191816B1 patent drawingFigure 1
  • EP4191816B1 patent drawingFigure 2
  • EP4191816B1 patent drawingFigure 3a~3b

AI summary

A charging circuit (113), a terminal device (11), an adapter (14), and a charging system (10) and method are disclosed, and are mainly applied to a charging process of the terminal device (11). The terminal device (11) may be charged by using an adapter (14) having no electrolytic capacitor, which is conducive to achieving miniaturization of the adapter. When a voltage of a charging interface (111) of the terminal device (11) is low, the charging circuit (113) may discharge by using a terminal battery (112), to maintain the voltage of the charging interface (111). The charging circuit (113) may also decrease a charging current provided to the terminal battery (112), to maintain the voltage of the charging interface (111). The voltage of the charging interface (111) may be equivalent to a voltage of an output interface of the adapter (14). Therefore, the charging circuit (113) can maintain the voltage of the output interface of the adapter (14) to be not excessively low, thereby preventing the adapter (14) from stopping working.