Switched-Capacitor DC-DC Converter for Lossless Ratio Switching
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Solution Overview
Problem
Inductor-less power converters face limitations in switching between discrete conversion ratios, resulting in energy loss and reduced efficiency compared to inductor-based alternatives.
Innovation Solution
A switched capacitor converter with cascaded stages and a control unit that maintains equal steady-state voltages across flying capacitors during switching, allowing lossless transitions between conversion ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If inductor-less switched capacitor designs are used, then the converter achieves smaller form factor and higher efficiency, but the converter suffers from limited discrete conversion ratios and energy loss when switching between ratios
Solution Approach 1:
The patent maintains equal steady-state voltages across all flying capacitors regardless of the conversion ratio setting. This equipotential condition ensures that when switching between different conversion ratios, no energy is lost due to voltage mismatches or discharge/charge cycles of the flying capacitors. The control unit configures switching blocks to achieve this equal voltage distribution across capacitors C1, C2, C3, and C4 for all predefined conversion ratio settings.
2Volume of moving object
If inductor-less switched capacitor designs are used, then the converter achieves smaller form factor, but the converter has limited discrete number of conversion ratios unlike inductor-based alternatives
Solution Approach 1:
The patent divides the power conversion function into multiple cascaded capacitor stages (at least four flying capacitors C1-C4), with each stage contributing to the overall voltage multiplication. This segmentation allows the converter to achieve higher conversion ratios and greater versatility while maintaining a compact form factor, as each capacitor stage can be independently controlled through switching blocks to achieve different voltage ratios.
3Adaptability or versatility
If multiple conversion ratios are implemented in inductor-less converters, then the converter provides more versatility, but switching between ratios results in energy loss that lowers overall performance
Solution Approach 1:
The patent maintains equal steady-state voltages across all flying capacitors regardless of the conversion ratio setting. This equipotential condition ensures that when switching between different conversion ratios, no energy is lost due to voltage mismatches or discharge/charge cycles of the flying capacitors. The control unit configures switching blocks to achieve this equal voltage distribution across capacitors C1, C2, C3, and C4 for all predefined conversion ratio settings.
Solution Approach 2:
The patent pre-configures multiple switching block arrangements corresponding to different predefined conversion ratio settings. Each switching block is designed in advance to connect the flying capacitors in specific configurations that maintain equal steady-state voltages. This preliminary configuration allows instant switching between ratios without energy loss, as the transition paths are pre-established to preserve voltage equality across all capacitors.
Data Source
AI summary
An inductor-less power converter for converting an input voltage at an input terminal to an output voltage at an output terminal is provided, with a conversion ratio between the input and output voltage. The converter can be an inductor-less power converter which is configured for Direct Current, DC, to DC, DC-DC conversion of an input voltage to an output voltage. The input voltage is provided at an input terminal pair whereas the output voltage is provided at an output terminal pair. The ratio between the input voltage and the output voltage defines the conversion ratio, which may be either larger than one or smaller than one, meaning that the voltage may be stepped-up or stepped-down and thus increased or lowered.