Study On High Step Down Buck Converter With Active Floating Charge Landing

With the rapid development of computer and Internet technology,all capabilities of CPU have been improved greatly, such as the capability and speed of information processing, which result in the increase of its load current with a more and more lower load voltage.Therefore the power supply modules must be improved to satisfy the need of the development of CPU. In this case power electronics,especially the rapidly improved power switching technology, provide a solution of the power supply.This paper first presents a description regarding the requirement for future power supply technology caused by the development of CPU. This paper concentrates on the study of typical topology and control methods of some non-isolated 12V input voltage regular module which supply for CPU by analyzing the advantages and disadvantages of the topology and control methods.Because voltage regular module (VRM) has the characteristic of low output voltage and high output current,this paper applies active floating charge landing (FCL) technology in the conventional Buck converter,by which a high step down Buck converter with FCL can be obtained.With a FCL,the input or output voltage of the converter can be lowered.This converter can expand the duty cycle and reduce the output voltage more easily and reduce the ripple of the output voltage. In addition it has the characteristic of nice dynamic response and it is suitable for future CPU.Main work in this paper:â‘ Reviewed the development of VRM,and then studyed on the characteristics of non-isolated Buck converter and their advantages and disadvantages based on analyzing their operation principle.â‘¡Based on the principle of FCL,applied it in a conventional Buck converter. By comparing its different places in Buck converter, this paper proposed a high step down Buck converter with FCL.Its operation principle and structure when the switches are at different sates were presented in detail. Function of high step down had been proved,according to which conversion ration of this converter can be deduced.â‘¢According to the comparison among different voltage control mode and current control mode , analyzed the control principle and their advantages and disadvantages.And applied charge control in the high step down Buck converter with FCL , established the control system structure. â‘£Simulations regarding the steady state, input voltage disturbance and load disturbance of this converter have been carried out with Saber, and results indicated the feasibility of this method and converter studied in this paper.