Load-Adaptive Phase-Shifted Full-Bridge Leg Switching
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Solution Overview
Problem
Existing phase-shifted full-bridge converters face difficulties in implementing soft switching at high frequencies due to large primary-side losses under heavy loads and failure to switch softly under light loads, limiting their application flexibility and efficiency.
Innovation Solution
A controller is introduced to dynamically switch between two working states of the phase-shifted full-bridge circuit based on load levels, adjusting the leading and lagging legs to optimize soft switching and reduce losses, using a resonant module and clamping module to facilitate efficient energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the existing control method is used with fixed leading and lagging legs, then the converter can operate under heavy load with both legs implementing soft switching, but the primary side loss becomes large and the lagging leg fails to implement soft switching under light load
Solution Approach 1:
The patent dynamically switches the roles of leading and lagging legs based on load conditions. Under heavy load, the first leg is leading and the second leg is lagging; under light load, the roles are reversed. This dynamic switching enables soft switching to be implemented in both legs across different load conditions, reducing primary side losses while maintaining reliable soft switching operation.
2Productivity
If the existing control method is used, then heavy load operation is supported, but the method is difficult to apply to high switching frequency scenarios due to light load soft switching failure
Solution Approach 1:
The patent implements dynamic role switching between leading and lagging legs based on load detection. When light load is detected, the controller switches which leg serves as leading and which as lagging, ensuring that soft switching can be maintained across the full load range. This enables high switching frequency operation while maintaining soft switching reliability under both light and heavy load conditions.
3Adaptability or versatility
If a fixed working state is used, then the control method is simple, but the adaptability to different load conditions is poor
Solution Approach 1:
The patent uses dynamic detection of load conditions to switch between different working states (different leading/lagging leg configurations). This enables the system to adapt to varying load conditions while maintaining soft switching performance. The complexity increase is minimal, involving only load detection and switching control logic, while significantly improving adaptability across light and heavy load scenarios.
Data Source
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AI summary
This application provides a controller for controlling a phase-shifted full-bridge circuit, a power supply module, and an electronic device, so that a loss is small in a full load range without adding an additional component. The phase-shifted full-bridge circuit includes a first leg and a second leg, the first leg includes a first high-side switch and a first low-side switch, and the second leg includes a second high-side switch and a second low-side switch. A working state of the phase-shifted full-bridge circuit includes a first working state and a second working state. The controller is configured to: detect a load level of a load circuit coupled to the phase-shifted full-bridge circuit, and control, based on the load level, the phase-shifted full-bridge circuit to switch the running working state When the phase-shifted full-bridge circuit runs in the first working state, the first leg is a leading leg, and the second leg is a lagging leg. When the phase-shifted full-bridge circuit runs in the second working state, the first leg is a lagging leg, and the second leg is a leading leg.