Coupled Step-Down Converter Stages for Lower Isolation Voltage
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Solution Overview
Problem
Existing switched-mode power supplies face high insulation requirements across isolation gaps due to varying grounding options, leading to stringent demands on insulation distances and materials, especially at high input voltages.
Innovation Solution
A switched-mode power supply design incorporating two coupled step-down converter stages, each connected to the positive and negative input voltage, with coils wound on a common core, and controlled together to create a symmetrical voltage drop across both stages, reducing insulation voltage across the isolation gap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single high-power switching regulator is used, then the component count is reduced, but the current stress and thermal management become more difficult
Solution Approach 1:
The patent divides a single high-power switching regulator into multiple lower-power switching regulator stages connected in series. Each stage handles a portion of the total power conversion, reducing the current stress and thermal load on individual components while maintaining the overall power conversion function.
2Device complexity
If a single high-power switching regulator is used, then the circuit structure is simplified, but the thermal management becomes more difficult
Solution Approach 1:
The patent segments the power conversion function into multiple stages, distributing the thermal load across several smaller power dissipation sources rather than concentrating it in a single high-power regulator. This improves heat dissipation and thermal management.
Solution Approach 2:
The patent introduces an additional dimensional aspect to thermal management by distributing power conversion across multiple physical locations and thermal zones, allowing for better heat distribution and dissipation pathways rather than concentrating thermal load in a single location.
3Reliability
If multiple switching regulators are used in series, then the current stress on each regulator is reduced, but the device complexity increases
Solution Approach 1:
The patent merges multiple switching regulator stages into a unified power conversion system with shared control logic and coordinated operation. This integration approach manages the complexity of multiple regulators by providing a cohesive control framework that simplifies the overall system management.
4Loss of energy
If multiple switching regulators are used in series, then the power conversion efficiency is improved, but the device complexity increases
Solution Approach 1:
The patent combines multiple switching regulator stages into an integrated system where the cumulative effect of each stage improves overall power conversion efficiency. The shared control and coordinated operation of multiple stages reduce energy losses compared to a single high-stress regulator.
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 effectively reduces insulation voltage requirements across the isolation gap, allowing easier compliance with safety standards and minimizing insulation material needs, regardless of input and output grounding configurations.
Implementation Method 1
a first switching regulator (220) having an isolated forward converter topology... a transformer (204) coupled between the switch (202) and the second switching regulator (230)
Implementation Method 2
a second switching regulator (230) having an isolated buck converter topology... a transformer (204) coupled between the switch (202) and the second switching regulator (230)
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
The invention relates to a switched-mode power supply (400, 500, 600), having: an input circuit (401) powered by an input voltage (VIN); an output circuit (402), coupled to the input circuit, for providing an output voltage (VOUT); and a DC isolating element (103) between the input circuit (401) and the output circuit (402), which isolating element is designed to observe a prescribed safety requirement in regard to isolation between the input voltage (VIN) and the output voltage (VOUT), wherein the input circuit (401) comprises two coupled step-down converter stages (403), of which a first step-down converter stage (404) in the positive input voltage (+VIN) and a second step-down converter stage (405) in the negative input voltage (-VIN) are connected upstream of the DC isolating element (103).