Single-Stage Battery Charger With Hybrid Converter Loss Reduction
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Solution Overview
Problem
Dual-stage battery charging systems are cost-ineffective and inefficient due to high power losses and complex architectures, particularly in fast charging modes where large currents and multiple power switches lead to excessive heat and reduced battery operating time.
Innovation Solution
A single-stage battery charging system incorporating a hybrid converter with a switched capacitor converter and an isolation switch, configured to operate in various modes such as 2:1 or 1:2 charge pump modes, and a three-level boost or buck converter, to simplify the charging process and reduce power dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a dual-stage battery charging system is used, then charging capability is achieved, but power losses are excessive and system complexity increases
Solution Approach 1:
The patent combines the buck converter and boost converter into a single integrated circuit structure that operates as a single-stage charging system. The circuit uses shared components including capacitors C1-C4, inductors L1-L2, and switches S1-S4 that can operate in different configurations to achieve both buck (step-down) and boost (step-up) conversion functions, eliminating the need for separate dual-stage converters and reducing overall power losses.
Solution Approach 2:
The charging circuit is designed with multi-functional capability where the same hardware components can operate in different modes depending on the charging requirements. The circuit can function as a buck converter when input voltage exceeds battery voltage, as a boost converter when input voltage is lower than battery voltage, and as a direct connection mode, providing universal charging capability across different voltage conditions without requiring multiple dedicated circuits.
2Speed
If fast charging mode is used, then charging speed is improved, but heat generation and power dissipation increase
Solution Approach 1:
The patent implements dynamic switching between different charging modes (fast charging, standard charging, pre-charging) based on real-time battery voltage and current conditions. The control circuit monitors battery state and automatically adjusts the charging parameters and mode, enabling fast charging when conditions permit while switching to lower-power modes when heat generation becomes excessive, thus optimizing charging speed while managing thermal characteristics.
3Adaptability or versatility
If multiple power switches are used in dual-stage system, then voltage conversion is achieved, but device complexity and cost increase
Solution Approach 1:
The patent merges the functionality of multiple power switches from separate buck and boost converters into a unified set of switches (S1-S4) that share common circuit nodes and capacitors. The switches are configured in a bridge-like structure where they can be selectively activated to achieve different voltage conversion modes, reducing the total number of isolated power switch components while maintaining full voltage conversion capability.
4Loss of energy
If dual-cell battery configuration is used, then input current is reduced, but additional system cost is incurred
Solution Approach 1:
The charging circuit is designed to universally support both single-cell and dual-cell battery configurations through its multi-functional voltage conversion capability. The same circuit can operate in buck mode for single-cell charging, in boost mode for dual-cell charging, or in direct connection mode, providing adaptable charging solutions without requiring separate dedicated circuits for different battery types, thereby reducing overall system cost.
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
The single-stage system reduces power losses by half, extends battery operating time, and eliminates the need for expensive buck-boost converters, while maintaining efficient charging capabilities across different input voltages and modes.
Implementation Method 1
An inductor and a first flying capacitor, wherein the inductor is connected to a midpoint of the plurality of first power switches
Implementation Method 2
a switched capacitor converter comprising a plurality of second power switches connected in series, and a second flying capacitor
Data Source
AI summary
A single-stage battery charging system includes a hybrid converter comprising a plurality of first power switches connected in series, an inductor and a first flying capacitor, wherein the inductor is connected to a midpoint of the plurality of first power switches, a switched capacitor converter comprising a plurality of second power switches connected in series, and a second flying capacitor, and an isolation switch coupled between the midpoint of the plurality of first power switches and a midpoint of the plurality of second power switches.