Anti-Backflow Charging Circuit With Dual Current Detection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing charging solutions for mobile terminals suffer from current backflow issues when the charger is unplugged, leading to misleading charging indications and user confusion.

Innovation Solution

An anti-backflow charging circuit with input and output current detection circuits and a control module to disconnect the charging path when input current is below a threshold and battery output current is above a threshold, preventing current backflow and accurately detecting charging state changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If current detection circuits and control module are added to detect and prevent backflow, then charging reliability is improved, but device complexity increases

Engineering Contradiction:
Improvecharging reliabilityVSAvoidcircuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The charging circuit is segmented into distinct functional modules: input current detection circuit, output current detection circuit, control module, and charging circuitry. Each module performs a specific function, allowing independent optimization and fault isolation while maintaining overall system reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control module performs preliminary detection of input and output currents before backflow occurs. By continuously monitoring current directions and comparing them against expected charging patterns, the system identifies backflow conditions early and disconnects the charging path preventively, avoiding the need for complex corrective mechanisms.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If dual current detection circuits are implemented to accurately detect backflow, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvecurrent detection precisionVSAvoiddetection circuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The input current detection circuit and output current detection circuit are positioned at different locations in the charging path, each optimized for its specific measurement task. The input detection circuit monitors charger current while the output detection circuit monitors battery current, allowing specialized detection strategies at each location without requiring a single complex universal detector.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The control module acts as an intermediary that receives detection signals from both current detection circuits, processes the information, and makes disconnection decisions. This mediator architecture allows the detection circuits to remain relatively simple while achieving precise backflow detection through coordinated multi-point monitoring.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4274051B1Anti-backflow charging circuit and electronic device
Publication Date: 2025.07.02 VIVO MOBILE COMM CO LTD
  • EP4274051B1 patent drawingFigure 1~2
  • EP4274051B1 patent drawingFigure 3~4
  • EP4274051B1 patent drawingFigure 5~6

AI summary

Embodiments of this application provide an anti-backflow charging circuit and an electronic device. The anti-backflow charging circuit includes: a charging circuit, an input current detection circuit, an output current detection circuit, and a control module. An input of the charging circuit is connected to a power adapter, and an output of the charging circuit is connected to a battery. The input current detection circuit is connected between the power adapter and the charging circuit, to detect an input current. The output current detection circuit is connected between the charging circuit and the battery, to detect a battery output current. The control module is separately connected to the charging circuit, the input current detection circuit, and the output current detection circuit, and is configured to control, if it is detected that the input current is less than a first current threshold and the battery output current is greater than a second current threshold, a path between the input and the output of the charging circuit to be disconnected.