Synchronous Rectification Control Device for Phase Shift Full Bridge Converter
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Solution Overview
Problem
Conventional phase shift full bridge converters with secondary side synchronous rectification schemes suffer from high losses and a narrow synchronous rectification capability range due to inefficient current management and the influence of inductance, leading to reduced power conversion efficiency and increased costs.
Innovation Solution
A synchronous rectification control device that detects the edges of winding voltages in the secondary side of a transformer, measures the period between these edges, and estimates the OFF timing for synchronous rectification switches, allowing for optimal control and minimizing losses without requiring additional signals from the primary side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional phase shift full bridge converters with secondary side synchronous rectification schemes are used, then power conversion is achieved, but high losses occur and synchronous rectification capability range is narrow due to inefficient current management and inductance influence
Solution Approach 1:
The synchronous rectification control device autonomously detects winding voltage edges and measures periods to estimate OFF timing for synchronous rectification switches without requiring additional control signals from the primary side, enabling the system to self-optimize its rectification capability range while minimizing losses
Solution Approach 2:
The control device dynamically adjusts the OFF timing parameter of synchronous rectification switches based on real-time measurement of winding voltage periods, optimizing the rectification capability range and minimizing energy losses across varying operating conditions
2Measurement precision
If additional signals are transferred from primary side to secondary side for synchronous rectification control, then control precision is improved, but device complexity and cost increase
Solution Approach 1:
The synchronous rectification control device autonomously detects winding voltage edges and measures periods to estimate OFF timing for synchronous rectification switches without requiring additional control signals from the primary side, enabling the system to self-optimize its rectification capability range while minimizing losses
Solution Approach 2:
The invention extracts the control function from the primary side by implementing autonomous edge detection and period measurement capabilities directly in the secondary side control device, eliminating the need for additional signal transfer mechanisms and reducing overall system complexity
Data Source
AI summary
A synchronous rectification control device achieves high power conversion efficiency without supplying additional signal to a secondary side from a primary side. An insulated type switching power supply provides such a synchronous rectification control device. An output power is regulated based on a phase difference between two half bridges in the primary side. In the secondary side of the full bridge converter circuit, a center tap is lead out from the secondary windings of a transformer to obtain two symmetrical sections of windings. A device for detecting winding voltage observes winding voltages at terminals of the sections of windings. The synchronous rectification control circuit controls transistors and MOSFETs connected to the secondary windings to make the transistor in the ON or OFF state depending on the current flow in the secondary windings.