Reconfigurable Switched-Capacitor Ladder for Wide-Ratio Conversion
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Solution Overview
Problem
Conventional switched-capacitor power converters (SCPCs) are limited in their ability to achieve high efficiency across a wide range of input-to-output voltage ratios, making them unsuitable for AC-DC conversion and high-voltage applications.
Innovation Solution
A reconfigurable ladder switched-capacitor converter with a switch matrix that allows dynamic connection of input and output terminals to different capacitor nodes, enabling flexible voltage conversion ratios and embedded power factor correction capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional switched-capacitor power converters use a fixed ladder network topology, then the structure is simple and easy to manufacture, but the number of ideal voltage conversion ratios is limited
Solution Approach 1:
The patent applies dynamics by making the ladder network reconfigurable through switch matrices that allow dynamic changing of connection topologies. The converter can switch between different ladder configurations (e.g., 2:1, 3:1, 4:1 division ratios) to achieve multiple ideal voltage conversion ratios, transforming a static structure into a dynamic one that adapts to different operating conditions
Solution Approach 2:
The patent segments the converter into modular components: multiple capacitor strings (first capacitors C1a-C1d and second capacitors C2a-C2d), switch matrices with multiplexers (input MUXi, output MUXo, bypass MUXbp), and controllable switch banks. This segmentation allows independent control of each segment to achieve different conversion ratios while maintaining manufacturing simplicity through standardized modular units
2Adaptability or versatility
If switched-capacitor power converters operate with varying input/output voltages, then the adaptability to different applications is improved, but the efficiency drops outside limited voltage ratio ranges
Solution Approach 1:
The control circuit dynamically adjusts the ladder network configuration based on real-time input voltage Vin and output voltage Vout measurements. When operating conditions change, the control circuit reconfigures the switch matrices to maintain the optimal conversion ratio, ensuring the converter operates at peak efficiency across varying voltage conditions rather than being limited to fixed ratios
Solution Approach 2:
The patent implements feedback control where the control circuit continuously monitors Vin and Vout, compares the actual conversion ratio with the ideal ratio, and adjusts the switch matrix configurations accordingly. This closed-loop feedback ensures the converter maintains high efficiency by operating at or near ideal conversion ratios even when input/output voltages vary
3Power
If high-voltage capacitors are used in switched-capacitor power converters, then the converter can handle high-voltage applications, but the size and cost increase significantly
Solution Approach 1:
The patent segments the voltage handling function across multiple series-connected capacitor strings. Each capacitor (C1a-C1d, C2a-C2d) operates at a fraction of the total input voltage, allowing the use of low-voltage capacitors that are smaller and cheaper. For example, in a 400V AC-DC converter, each capacitor string handles approximately 100V instead of the full 400V, enabling standard low-voltage capacitor technology to be used
Solution Approach 2:
The same low-voltage capacitors serve multiple functions: voltage division, energy storage, and power factor correction. The capacitor strings are configured to provide both the voltage conversion function and the power factor correction function, eliminating the need for separate high-voltage capacitors and reducing overall component count and cost
4Reliability
If power factor correction is implemented separately from the main converter, then the power factor correction performance is optimized, but the device complexity and component count increase
Solution Approach 1:
The patent merges the power factor correction function with the main voltage conversion function by using the same capacitor strings and switch matrices for both purposes. During certain switching phases, the capacitor strings are configured to provide power factor correction by charging and discharging in synchronization with the AC input voltage, eliminating the need for separate PFC circuitry while maintaining effective power factor correction performance
Data Source
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AI summary
The present disclosure relates to a switched-capacitor converter comprising: a first terminal; a second terminal; a switched-capacitor ladder network comprising a plurality of serially connected first capacitors defining a plurality of flying capacitor nodes; a plurality of serially connected second capacitors defining a plurality of output capacitor nodes, wherein nodes of the flying capacitor nodes can be connected to nodes of the output capacitor nodes in a plurality of ladder converter configurations to perform a switched-capacitor ladder power conversion; and a switch matrix configured to connect the first terminal to different flying capacitor nodes and/or configured to connect any flying capacitor node to any other flying capacitor node or output capacitor node10 according to different switch configurations according to different switch configurations. The disclosure further relates to a switched-capacitor converter assembly comprising a plurality of serially and/or parallel connected switched-capacitor reconfigurable switched-capacitor ladder converters. The disclosure further relates to methods for converting an input into an output voltage using a switched-capacitor converter and for operating an assembly of switched-capacitor converters.