基于并联同步整流技术的密封结构LLC谐振电源的散热优化设计

Heat Dissipation Optimization Design of LLC Resonant Power Supply Based on Parallel Synchronous Rectification Technology

LLC谐振变换器以其能够在全负载范围内实现零电压软开关,在高工作频率下实现高效率,满足了高功率密度、小体积开关电源的需求,并可实现开关电源的密封结构设计。然而在高开关频率下,其功率管的损耗也相应增大,在密封结构下对功率管散热问题的解决成为开关电源设计的要点。通过并联同步整流技术,充分利用MOS管通态电阻低的特点,采用并联MOS管对输出侧电流进行分流,从而大大减少了开关管的整流损耗,提高了变换器的整体效率;并通过对热沉的改进设计,采用热管改善了散热器的散热效果,解决了密封结构开关电源的散热问题,提高了开关电源高温工作下的可靠性。

The LLC resonant converter can achieve zero voltage soft switching in the full load range,which can achieve high efficiency at high operating frequency,and can meet the high power density,the requirement of small volume switch power supply,and the sealing structure design of switching mode power supply can be realized.However,at high work frequency,the power lose of the MOSFETs will be greater,thus the problem of heat dissipation of the MOSFETs will be of great importance to solve when a seal structure power source was designed.Through the parallel synchronous rectification technology,the characteristics of MOS tube on state resistance low is utiliaze fully.The shunt MOS tube is used to split the output side current,thereby greatly reducing the commutation loss of the switching tube and improving the overall efficiency of the converter.Through the improvement of heat sink design,the heat pipe is used to improve the heat dissipation effect of the radiator,and the heat dissipation of the switching mode power supply of the sealed structure is solved,and the reliability of the switching mode power supply is improved.