Switched-Capacitor DC-DC Converter: Evolution from Transformer Model to Circuitry
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摘要: 开关电容(Switched Capacitor, SC) DC-DC转换器在很多领域有着广泛的应用。为应对大电压转换比(Voltage Conversion Ratio, VCR)的情况,前人提出了诸多拓扑结构。常用的拓扑结构包括Dickson,Cockcroft-Walton,Series-Parallel,Ladder,Fibonacci,Divider等等。这些拓扑结构有着各自的性能特点,适用于不同的场景。然而,对于这些不同的拓扑结构是如何产生的,本质的区别是什么,各自的优缺点是什么,并无直观的解释和分析。因此,该文从开关电容DC-DC转换器的等效变压器模型入手,分析了各个拓扑之间的本质区别,并展示了从等效模型到实际电路的演进过程,解释了规则和原因。Abstract: SC DC-DC converters have wide applications. Previous works proposed multiple topologies for a high voltage conversion ratio scenario, such as Dickson, Cockcroft-Walton, Series-Parallel, Ladder, Fibonacci and Divider. They have their own features, fitting different applications. However, it is unclear how these topologies are generated, what the main differences are between them, and what the advantages and disadvantages are. Therefore, this paper starts from the transformer model of the SC converters, analyzing the difference among them. Then, it is demonstrated how the SC converters evolve from the model to the real circuitries, where multiple intuitive understanding can be obtained.
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Key words:
- Switched-capacitor /
- DC-DC converter /
- Transformer model /
- Evolution
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图 12 常见降压型 SC 拓扑的 SSL 和 FSL 性能对比[6]
表 1 常见降压型SC拓扑的开关和电容的耐压汇总
结构 开关耐压 电容耐压 优缺点 4:1 Divider 2×VO, 1×VO 2×(2×VO), 1×VO SSL与FSL性能中等 4:1 Dickson 3×(1×VO) 3×VO, 2×VO, 1×VO SSL性能差 FSL性能好 4:1 CW 3×(1×VO) 2×VO, 2×VO, 1×VO SSL性能差 FSL性能好 4:1 S-P 3×VO, 2×VO, 1×VO 3×(1×VO) SSL性能差 FSL性能好 4:1 Ladder 3×(1×VO) 5×(1×VO) SSL性能差 FSL性能好 5:1 Fibonacci 2×VO, 2×(1×VO) 3×VO, 2×VO, 1×VO SSL与FSL性能中等 -
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