Resonant Conversion Circuit Topology for High-Ratio Voltage Conversion
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Solution Overview
Problem
The Switching Tank Converter (STC) has a complex circuit structure and low efficiency in high voltage conversion ratios, making it inadequate for applications requiring high power density and efficiency.
Innovation Solution
A conversion circuit with a full-bridge rectifier and resonant units connected in series with the transformer, allowing for increased voltage conversion ratios by directly flowing current through the primary winding to the output, reducing transformer losses and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a traditional STC is used for voltage conversion, then the circuit structure is simple, but the efficiency is low and power density is reduced in high voltage conversion ratio applications
Solution Approach 1:
The patent divides the voltage conversion process into two independent stages: a first stage converter (48V-4V) and a second stage converter (4V-0.8V). This segmentation allows each stage to operate at its optimal efficiency point, with the first stage handling the high voltage conversion ratio using a transformer-based resonant converter, and the second stage handling the final regulation using a synchronous rectifier, thereby resolving the contradiction between simple structure and high efficiency.
Solution Approach 2:
The patent introduces an intermediate voltage bus (4V) between the input (48V) and output (0.8V) stages. This intermediary voltage level serves as a buffer that decouples the high voltage conversion ratio requirement from the final low voltage output, allowing the first stage to use a transformer for efficient high-ratio conversion while the second stage handles the final regulation, thus improving overall conversion efficiency without excessive circuit complexity.
2Loss of energy
If a two-stage cascaded conversion structure is used, then the voltage conversion efficiency is improved, but the device complexity is increased
Solution Approach 1:
The patent merges the rectifier functions into both stages of the conversion process. The first stage uses a full-bridge rectifier with synchronous rectification, and the second stage also incorporates synchronous rectification. This merging of rectifier functions with the conversion stages eliminates the need for separate rectification circuits, reducing overall device complexity while maintaining high conversion efficiency through reduced conduction losses.
3Power
If the voltage conversion ratio is increased to meet processor power requirements, then the power density is improved, but the transformer losses increase
Solution Approach 1:
The patent segments the high voltage conversion ratio (48V to 0.8V, a 60:1 ratio) into two manageable stages: 48V to 4V (12:1 ratio) in the first stage, and 4V to 0.8V (5:1 ratio) in the second stage. By dividing the total conversion ratio, each transformer operates at a more efficient turns ratio, reducing magnetic core losses and copper losses while still achieving the required high power density for processor applications.
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 achieves higher voltage conversion ratios with reduced transformer losses and complexity, improving power density and efficiency compared to traditional STC designs.
Implementation Method 1
a resonant inductor Lr and a resonant capacitor Cr, wherein the resonant inductor Lr and the resonant capacitor Cr form a resonant circuit
Implementation Method 2
a transformer Tr having a primary winding Tr1 and a secondary winding Tr2
Data Source
Figure 1~2
Figure 3A~3B
Figure 3C~5
AI summary
The invention provides a conversion circuit for converting input voltage into output voltage, including: a full-wave rectifier circuit including first and second branches connected in parallel, and each including a secondary winding and a rectifier switch; a first switch branch connected to midpoint of the first branch, and including first to fourth switches connected in series; a first resonant unit connected between connection node of the first and second switches and midpoint of the second branch; a second resonant unit connected between connection node of the third and fourth switches and midpoint of the second branch; a first primary winding connected in series to the first resonant unit; and a capacitor connected between connection node of the second and third switches and midpoint of the second branch. The conversion circuit of the invention improves conversion efficiency while maintaining smaller voltage stress on switches.