Resonant Conversion Circuit Topology for High-Ratio DC Voltage Step-Down
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Solution Overview
Problem
Switched Tank Converters (STCs) face complexity and low efficiency in achieving high voltage conversion ratios, leading to increased switch loss and reduced power density in data center applications.
Innovation Solution
A conversion circuit design that incorporates a full-bridge rectifier circuit with resonant units and a transformer, allowing for a higher voltage conversion ratio by directly flowing primary current to the output terminal without induction, reducing transformer loss and volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If Switched Tank Converters (STCs) are used to achieve high voltage conversion ratios, then voltage conversion capability is improved, but device complexity and efficiency deteriorate due to increased switch loss
Solution Approach 1:
The patent divides the voltage conversion function into two distinct stages: a first stage converter (48V-4V) and a second stage converter (4V-0.8V). This segmentation allows each stage to be optimized independently, with the first stage handling the bulk of the voltage reduction using a simplified topology, and the second stage providing fine-grained regulation. This resolves the contradiction by achieving high overall voltage conversion ratio without requiring a single complex STC stage.
Solution Approach 2:
The patent extracts the resonant tank and transformer components from the traditional STC architecture to create a simplified first stage converter. By removing the complex switched tank structure and using only the essential resonant inductor, capacitor, and transformer elements, the design achieves high voltage conversion ratio while significantly reducing circuit complexity and switch loss.
2Power
If Switched Tank Converters (STCs) are used to achieve high voltage conversion ratios, then voltage conversion capability is improved, but power density deteriorates due to reduced efficiency
Solution Approach 1:
By segmenting the voltage conversion into two stages, the patent reduces the voltage stress on switches in each stage. The first stage switches handle 48V to 4V conversion with lower frequency and loss, while the second stage switches handle 4V to 0.8V conversion with higher efficiency. This segmentation dramatically reduces total switch loss compared to a single high-ratio STC stage.
Solution Approach 2:
The patent changes the operating parameters by using different switching frequencies and topologies for each stage. The first stage operates at lower frequency with resonant soft-switching to minimize loss, while the second stage uses high-frequency BUCK converter with PWM control for efficient regulation. This parameter optimization resolves the energy loss issue.
3Power
If traditional STC topology is used, then voltage conversion is achieved, but transformer volume and loss increase
Solution Approach 1:
The patent extracts the transformer from the second stage converter, using it only in the first stage for the 48V to 4V conversion. The second stage uses a BUCK converter topology that eliminates the transformer entirely, replacing it with simple inductors and switching components. This dramatically reduces total transformer volume and associated losses while maintaining the required voltage conversion capability.
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 design enhances efficiency and power density by increasing the voltage conversion ratio while minimizing transformer losses and volume, addressing the limitations of traditional STCs.
Implementation Method 1
a resonant inductor Lr and a resonant capacitor Cr, and a transformer Tr... a resonant unit 13 having the resonant capacitor Cr and the resonant inductor Lr connected in series
Implementation Method 2
a transformer Tr having a primary winding Tr1 and a secondary winding Tr2... the primary winding Tr1 and the secondary winding Tr2 of the transformer Tr
Data Source
Figure 1~2
Figure 3A~3B
Figure 3C~5
AI summary
The invention provides a conversion circuit for converting an input voltage into an output voltage, including: a first full-wave rectifier circuit including a first branch and a second branch connected in parallel, each including a winding and a rectifier switch connected in series to form a midpoint; a first switch branch including a first switch and a second switch connected in series to form a first connection node; and a first resonant unit connected between the first connection node and a midpoint of the second branch, wherein the first resonant unit is not connected in series to the windings of the transformer. The conversion circuit of the invention improves conversion efficiency while maintaining smaller voltage stress on switches.