学术论文

      同步整流Buck变换器的损耗分析

      The loss analysis of a synchronous rectification buck converter

      摘要:
      文中在以往只粗略计算电感损耗、电容损耗及开关损耗的基础上,以一款低电压大电流同步整流降压变换器为例,详细分析了各个元器件上功率损耗,包括电感上的铜损与铁损,电容等效串联电阻的损耗,MOSFET上的开关损耗、导通损耗、截止损耗、驱动损耗、寄生体二极管损耗等,从而得到直流降压变换器的整体损耗与实际效率.从效率曲线可以看出,变换器效率随着输出电流的增加而增加,并很快趋于饱和.而通过损耗分析可知,要降低损耗提高效率,尤其对于低电压大电流输出的降压变换器,不仅可以采用同步整流技术来降低导通压降,还可以根据各损耗所占比重大小选用更优元器件,如低直流电阻的电感,低导通电阻、低上升下降时间的NMOS管等.
      Abstract:
      A synchronous rectification buck converter with low voltage and high current is set as an example to analyze the dissipation of the buck converter more detailedly.Instead of just calculating inductance copper loss,capacitance loss and switching loss traditionally,the dissipationa nalysis in the thesis includes copper loss and iron loss of the inductor,equivalent series resistant loss of the capacitor,switching loss,conduction loss,cut-off loss,drive loss and body diode loss of the MOSFETs.Consequently,the total power loss and the operating efficiency can be achieved.From the efficiency curve,it is noted that the efficiency rises with the increasing of the output current and tends to be saturated quickly afterwards.In order to create the more efficient buck converter,particularly in the case of low output voltage and high output current,the technology of synchronous rectification can be applied to cut down the conduction voltage drop.Moreover,considering the different proportion of power loss in different parts,the superior components can be put into use,such as the inductor with low resistance,NMOS with low conduction resistance and low rise/fall time,etc.
      作者: 邵静宜
      Author: SHAO Jing-yi
      作者单位: 谢菲尔德大学电子与电气工程学院,英国谢菲尔德S102TN
      刊 名: 信息技术 ISTIC
      年,卷(期): 2017, (3)
      分类号: TP391 TM133
      在线出版日期: 2017年4月18日