Parallel Battery Charging Circuit with Master-Slave Current Distribution
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Solution Overview
Problem
Existing battery chargers for portable devices typically allow only single battery charging at a time, leading to lengthy recharge periods when multiple spare batteries are needed, and often require complex control circuitry to manage charge current distribution.
Innovation Solution
A battery charger system with a master charge manager and a slave charge manager, along with a cross-over controller, that allows simultaneous charging of multiple batteries by adjusting current distribution based on the charge status of each battery, ensuring efficient use of the available current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single battery is charged at a time using a portable charger, then the charging control circuitry is simple, but the recharge period becomes lengthy when multiple spare batteries are needed
Solution Approach 1:
The charging system is segmented into multiple independent charge pockets (first charge pocket, second charge pocket), each capable of charging a battery independently. This segmentation allows simultaneous charging of multiple batteries without requiring complex centralized control circuitry, thus reducing device complexity while eliminating the lengthy recharge period associated with single-battery charging.
2Loss of time
If multiple batteries are charged simultaneously using existing chargers, then the recharge period is reduced, but the control circuitry becomes unnecessarily complex
Solution Approach 1:
The charging system is divided into independent charge pockets with autonomous charging circuits. Each pocket operates independently with its own voltage detection and current control, eliminating the need for complex centralized control circuitry while enabling simultaneous charging of multiple batteries, thus reducing recharge period without increasing device complexity.
Solution Approach 2:
Each charge pocket is designed to autonomously manage its own charging process by detecting battery voltage levels and automatically adjusting charging current. The first charge pocket detects when its battery reaches full charge and automatically transitions to trickle charging, while the second charge pocket independently charges its battery. This self-service capability eliminates the need for complex inter-packet coordination circuitry.
3Adaptability or versatility
If sequential charging is used as described in Brake (US 5,780,991), then the charger can handle multiple batteries, but the charging process becomes time-consuming due to sequential operation
Solution Approach 1:
The charging system is segmented into multiple independent charge pockets that operate simultaneously rather than sequentially. Each pocket has its own charging circuit and control logic, allowing parallel charging of multiple batteries. This segmentation maintains adaptability to handle multiple batteries while dramatically reducing the total charging time compared to sequential operation.
4Speed
If priority-based fast charging is used as described in Johnson (US 5,028,859), then one battery is charged quickly, but the control logic becomes complex and other batteries wait longer
Solution Approach 1:
The charging system is divided into independent charge pockets, each with autonomous control logic that detects battery voltage and automatically adjusts charging current. The first charge pocket implements fast charging when battery voltage is below 4.2V, then automatically transitions to trickle charging at 4.2V. The second charge pocket operates independently with similar autonomous control. This segmentation enables fast charging speed without complex priority-based control logic, as each pocket self-regulates based on its own battery status.
Data Source
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Figure 2B
AI summary
A battery charger (100) includes a master charge manager (200), and a slave charge manager (300) coupled to the master charge manager (200). The master charge manager (200) is coupled to a power source (102) and one battery (106) and is configured to charge the one battery (106) with a first continuously decreasing portion of the available current after a voltage across the one battery (106) exceeds a first predetermined maximum voltage threshold. The slave charge manager (300) is coupled to the power source (102) and another battery (108) and is configured such that, while the master charge manager (200) charges the one battery (106) with the continuously decreasing portion of the available current, the slave charge manager (300) charges the other battery (110) with a continuously increasing portion of the available current. The total of the decreasing portion and the increasing portion are substantially equal to the current available from the power source (102).