DC-to-DC Converter Circuit with Series Inductor for EMI Reduction
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Solution Overview
Problem
Existing DC-to-DC converter circuits face issues with electromagnetic interference (EMI) due to increased jump frequencies of voltages at connection points, leading to radiation interferences and common-mode currents, which deteriorate EMI performance, especially when output power is enhanced by connecting switch elements in parallel.
Innovation Solution
A DC-to-DC converter circuit design where the secondary sides of the first and second branches are connected in series via an inductor, reducing jump frequencies and improving EMI performance by minimizing radiation interferences and common-mode currents, while also achieving zero-ripple output current at specific duty ratios, allowing for reduced conduction and copper losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If switch elements are connected in parallel to increase output power, then the output power is improved, but the jump frequency of voltages increases causing radiation interferences and common-mode currents
Solution Approach 1:
An intermediary inductor is introduced between the secondary rectifier circuits of parallel branches. This inductor acts as a mediator that decouples the voltage jump frequencies between different branches, preventing their superposition while maintaining the high output power capability of the parallel configuration.
Solution Approach 2:
The problematic voltage jump frequency superposition is extracted and isolated by placing an inductor in the common path. This separates the harmful high-frequency voltage jumps from the output, allowing the parallel switch configuration to maintain high power output without the EMI side effects.
2Power
If the secondary sides of parallel branches are connected in parallel, then the output power is increased, but the voltage jump frequencies superimpose causing EMI performance deterioration
Solution Approach 1:
An inductor is placed in the common secondary path to act as an intermediary element. This inductor prevents the direct superposition of voltage jump frequencies from parallel branches while still allowing the branches to contribute additively to the output power, thus maintaining both high power and good EMI performance.
3Power
If multiple parallel branches are used to enhance output power, then the power density is improved, but the complexity of the circuit increases
Solution Approach 1:
Multiple parallel branches are merged into a unified output structure with a common inductor. This combining approach maintains the power density benefits of parallel configuration while simplifying the overall circuit topology by using shared components and a standardized connection pattern.
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 proposed circuit design effectively decreases radiation interferences, reduces common-mode currents, and enhances EMI performance, achieving zero-ripple output current with reduced losses, thereby increasing power density and efficiency.
Implementation Method 1
a first inductor, a secondary side of the first branch and a secondary side of the second branch are connected in series via the first inductor
Implementation Method 2
The first branch 11 comprises a first transformer 111, a first primary switching circuit 112, and a first secondary rectifier circuit 113
Data Source
AI summary
The present application discloses a DC-to-DC converter circuit and a circuit board layout structure for the same. The DC-to-DC converter circuit is electrically connected between a first power supply side and a second power supply side, and comprises a first branch with a primary side coupled to the first power supply side and a secondary side coupled to the second power supply side; a second branch with a primary side coupled to the first power supply side and a secondary side coupled to the second power supply side; and a first inductor. The secondary sides of the first branch and the second branch are connected in series via the first inductor.