Flying Capacitor DC-DC Converter Layout for Lower-Voltage Switches
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Solution Overview
Problem
The use of switching elements with a withstand voltage of 300 V in high-operating-voltage applications results in limited efficiency gains due to conduction losses across multiple switching elements.
Innovation Solution
A DC-DC converter design featuring a first and second flying capacitor circuit connected in series and parallel to a high voltage side DC part, with a reactor connected between the low voltage side DC part and the midpoint of the first flying capacitor circuit, allowing for the use of switching elements with even lower withstand voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If switching elements with lower withstand voltage are used, then cost and conduction loss are reduced, but the number of switching elements required increases
Solution Approach 1:
Each flying capacitor circuit serves multiple functions: it provides voltage division, energy storage, and current path management. The switching elements within each circuit not only control power flow but also contribute to the overall voltage boosting through their series connection, making each component multi-functional and justifying the increased count through enhanced system capabilities.
Solution Approach 2:
Multiple flying capacitor circuits are nested in series, with each circuit containing its own set of switching elements and capacitors. This nested structure allows the system to achieve high voltage output by combining multiple lower-voltage stages, where each stage is self-contained but contributes to the overall function, creating a scalable architecture.
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
This design achieves even higher efficiency by enabling the use of switching elements with lower withstand voltage, reducing conduction and switching losses, and allowing for smaller component sizes and lower heat dissipation.
Implementation Method 1
a reactor connected between a positive side terminal of a low voltage side DC part and a midpoint of the first flying capacitor circuit
Implementation Method 2
a first flying capacitor circuit and a second flying capacitor circuit connected in series so as to be in parallel to a high voltage side DC part
Data Source
AI summary
A first flying capacitor circuit and a second flying capacitor circuit are connected in series so as to be in parallel to a high voltage side DC part. A reactor is connected to a positive side terminal of a low voltage side DC part and a midpoint of the first flying capacitor circuit. A midpoint of the second flying capacitor circuit is connected to a negative side terminal of the low voltage side DC part. A node between the first flying capacitor circuit and the second flying capacitor circuit is connected to an intermediate potential node of the high voltage side DC part.