Low-Voltage E-Cigarette Charging Circuit With Alternating Charge Stages

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Solution Overview

Problem

Existing electronic cigarettes face issues with low voltage charging, over-discharging, and safety concerns, leading to inefficient use and potential safety hazards due to unsafe battery operation, resulting in resource waste and environmental impact.

Innovation Solution

A low voltage battery charging control and protection circuit is introduced, utilizing an external extended charging circuit and charging integrated circuit, controlled by a microcontroller, to manage charging and protect the battery from over-discharge, ensuring safe and efficient charging by alternating charging modes and monitoring discharge cycles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the battery is charged at 0V using conventional IC charging, then the charging current is limited to about 100mA, but the charging time becomes excessively long (3-5 hours) and the battery may not be fully charged

Engineering Contradiction:
Improvecharging capability at low voltageVSAvoidcharging time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The charging process is divided into multiple voltage stages. The circuit segments the charging voltage into 0V-2.5V (using extended charging circuit), 2.5V-4.2V (using IC charging circuit), and 4.2V-4.35V (using extended charging circuit again), allowing each stage to use the most appropriate charging method for that voltage range

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The charging circuit dynamically switches between extended charging mode and IC charging mode based on the real-time battery voltage detected by the voltage detection module, optimizing charging efficiency at each voltage level

Inventive Principle:
Principle #15Dynamics

2Reliability

If the battery is protected by automatic shutdown at low voltage, then safety is improved, but the user cannot use the battery when needed (forceful startup required)

Engineering Contradiction:
Improvebattery safetyVSAvoidbattery usability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The voltage detection module continuously monitors battery voltage and provides feedback to the control module. When voltage is low, the system provides feedback warnings to the user and automatically prevents forceful startup, balancing safety with user awareness

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The circuit preemptively prevents unsafe operation by detecting low voltage conditions before the user can forcefully start the battery, and actively blocks the startup signal to avoid potential damage

Inventive Principle:
Principle #9Preliminary anti-action

3Use of energy by moving object

If the battery is allowed to discharge multiple times at low voltage, then the electrical energy is used to maximum degree, but safety issues occur (swelling, fluid leakage)

Engineering Contradiction:
Improveenergy utilizationVSAvoidsafety hazards
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The voltage detection module continuously monitors battery voltage during discharge and provides feedback to the control module. When voltage drops below the safety threshold, the system automatically cuts off discharge to prevent safety hazards while maximizing safe energy utilization

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system preemptively identifies when the battery approaches unsafe discharge levels and takes preventive action by automatically shutting down discharge before safety issues can occur

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3661007B1Low voltage charging control and protection circuit for electronic cigarette and method of charging the electronic cigarette using the circuit
Publication Date: 2026.05.06 SHENZHEN INNOKIN TECHNOLOGY CO LTD
  • EP3661007B1 patent drawingFigure 1
  • EP3661007B1 patent drawingFigure 2

AI summary

A low voltage charging control and protection circuit for an electronic cigarette is provided. The circuit includes an external extended charging circuit (EC) configured to charge a battery of the electronic cigarette at a first voltage. The circuit also includes a charging integrated circuit (IC) configured to charge the battery of the electronic cigarette at a second voltage. The first voltage is lower than the second voltage. The circuit further includes a microcontroller configured to control the external extended charging circuit (EC) and the charging integrated circuit (IC) to alternately charge the battery of the electronic cigarette based on a high or low level of a voltage of the battery.