Synchronous Rectification Controller Circuit Area Reduction
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Solution Overview
Problem
Existing insulated DC/DC converters, particularly LLC resonant converters, face challenges in achieving compact size due to the increased circuit area required for synchronous rectification controllers that control MOSFETs on the secondary side, which is necessary for improved efficiency.
Innovation Solution
A compact synchronous rectification controller is developed, featuring a shared pulse generator for two synchronous rectification transistors, a multiplexer for voltage selection, a driving circuit for switching, and a phase controller to prevent simultaneous switching, integrated on a single semiconductor substrate, reducing circuit area and allowing monolithic integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If synchronous rectification transistors are used on the secondary side to improve efficiency, then converter efficiency is improved, but circuit area increases due to the need for a synchronous rectification controller
Solution Approach 1:
The patent merges the control of two synchronous rectification transistors into a single integrated controller chip that includes both the synchronous rectification controller and pulse generator. This consolidation reduces the overall circuit area by eliminating separate discrete components and interconnections, while maintaining the efficiency benefits of synchronous rectification on the secondary side.
Solution Approach 2:
The integrated controller is designed to universally control multiple synchronous rectification transistors (including both same-side and opposite-side transistors) through a unified architecture. The controller incorporates multiplexers and shared pulse generation circuits that can manage multiple transistor gates, reducing the need for separate control circuits for each transistor and thereby minimizing circuit area.
2Area of stationary object
If a synchronous rectification controller is integrated on a single semiconductor substrate, then circuit area is reduced, but manufacturing complexity increases
Solution Approach 1:
The integrated controller is segmented into distinct functional modules including pulse generation circuits, multiplexers, driving circuits, and control logic. Each module is designed as a separate functional block within the semiconductor substrate, allowing for modular design and fabrication. This segmentation simplifies the manufacturing process by enabling standardized cell reuse and reducing design complexity despite the integrated nature of the circuit.
Data Source
AI summary
A synchronous rectification controller includes a first gate pin coupled to a gate of a first synchronous rectification transistor, a first drain pin coupled to a drain of the first synchronous rectification transistor, a second gate pin coupled to a gate of a second synchronous rectification transistor, a second drain pin coupled to a drain of the second synchronous rectification transistor, a source pin coupled to a ground, a multiplexer selecting a voltage applied to the first drain pin in a first state, and selecting a voltage applied to the second drain pin in a second state, a pulse generator generating a pulse signal based on an output voltage of the multiplexer, a driving circuit switching the first synchronous rectification transistor according to the pulse signal in the first state, and switching the second synchronous rectification transistor according to the pulse signal in the second state.