Multi-Phase Switch Control for LLC Converter Current Stress
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
LLC resonant converters used in power supply devices for displays face challenges in supplying low voltage and high current output, leading to large current stress, voltage ripple, and reduced lifespan due to overheated output capacitors.
Innovation Solution
A switch control device employing a multi-phase interleaving frequency modulation method that sums the output power of multiple converters, modulates the switching frequency based on load conditions, and controls the phase difference between gate signals to manage the switching operation of a multi-channel converter, reducing current stress and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single LLC resonant converter is used to supply high current output, then the power delivery capability is improved, but current stress and heat generation increase leading to reduced lifespan
Solution Approach 1:
The patent divides a single high-power converter into multiple parallel resonant converters (first and second converters). Each converter handles a portion of the total load, reducing the current stress and heat generation on individual components while maintaining the overall high power output capability. This segmentation allows the system to deliver high current without overheating any single converter.
2Reliability
If multiple converters are operated in parallel to reduce current stress, then converter lifespan is improved, but control complexity increases
Solution Approach 1:
The patent merges the control of multiple converters into a unified control system that generates synchronized gate signals for all power switches. The controller coordinates the switching operations of both converters, ensuring they operate in parallel with proper phase relationships. This unified approach simplifies control compared to independent control of each converter while maintaining the reliability benefits of parallel operation.
3Power
If high current is supplied through a single converter, then power delivery is improved, but voltage ripple increases
Solution Approach 1:
The patent segments the current delivery function across multiple parallel converters, each contributing to the total output current. This distribution of current paths reduces the ripple current through individual output capacitors and the overall output voltage ripple. The combined output of multiple converters provides smoother current delivery while maintaining high power capability.
Data Source
AI summary
The present invention relates to a switch control device, a multi-channel converter including the same, and a switch control method thereof. A multi-channel converter includes at least two converters, and each converter includes at least one power switch. The multi-channel converter supplies the sum of the output power of at least two converters to the load. The switch control device generates at least two gate signals switching operation of each of at least one power switch of at least two converters. The switch control device modulates a switching frequency of at least one power switch according to the load, determines the number of phases of the multi-channel converter according to the load, and generates a gate signal for the phase difference corresponding to the number of the determined phases between at least two gate signals to be generated.