Buck Converter with Segmented Inductors for Large Step-Down Ratios
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional buck converters experience high maximum current stress and conduction loss due to a small duty cycle when dealing with large step-down ratios, leading to inefficient voltage conversion.
Innovation Solution
The proposed buck converter design includes multiple inductors and auxiliary switches, with a controller managing their operation to adjust the duty cycle and reduce current stress, allowing for a larger duty cycle and smaller root mean square current through the main switch, thereby alleviating the stress and loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a conventional buck converter is used with a large step-down ratio, then the output voltage can be significantly reduced, but the duty cycle becomes small causing large current stress and conduction loss
Solution Approach 1:
The patent divides the single inductor into multiple inductors (first inductor, second inductor, third inductor) and introduces auxiliary switches to create separate current paths. This segmentation allows the main switch to operate with a larger duty cycle while the auxiliary switches handle current steering, thereby reducing the RMS current through the main switch and lowering conduction loss during large step-down conversion.
Solution Approach 2:
The auxiliary switches act as intermediaries that redirect current flow between different inductors and output terminals. By introducing these intermediary components, the patent enables the main switch to maintain a larger duty cycle without bearing the full burden of high current stress, thus resolving the contradiction between voltage conversion capability and conduction loss.
2Power
If a conventional buck converter is used with a large step-down ratio, then the output voltage can be significantly reduced, but the main switch endures large maximum current stress
Solution Approach 1:
The patent segments the current path by introducing auxiliary switches and multiple inductors, allowing the main switch to share current stress with auxiliary switches. This segmentation enables the main switch to operate with a larger duty cycle while distributing the maximum current stress across multiple components, thereby reducing the burden on the main switch.
Solution Approach 2:
The auxiliary switches perform partial current steering functions, handling a portion of the current that would otherwise flow through the main switch. This partial action by auxiliary components allows the main switch to endure reduced current stress while maintaining the required voltage conversion capability.
Data Source
AI summary
A buck converter includes: a first input terminal; a second input terminal; a first output terminal; a second output terminal; an internal node; a first inductor, a second inductor and a main switch connected in series between the first input terminal and the internal node; a third inductor connected between the internal node and the first output terminal; a fourth inductor connected between the second input terminal and the second output terminal; a first auxiliary switch connected between the internal node and the second output terminal; and a second auxiliary switch connected between the second input terminal and the first output terminal.