Research On Precisely Regulated Multi-output DC-DC Converter

With the development of modern communication and digital processing technology,the requirements for voltage accuracy,transient response and reliability of low voltage multi-output DC-DC converter are becoming higher and higher.In order to overcome the shortcomings of traditional multi-output switching power supply,such as insufficient voltage regulation accuracy and poor dynamic response,a new multi-output topology is proposed designed in this thesis.In this thesis,the common control methods of multi-output technology are discussed.Combined with the advantages and disadvantages of non-isolated topologies and isolated topologies,a two-stage topology cascade scheme is introduced.Based on the cascaded topology,a multi-output topology of leading edge modulation,with accurate voltage regulation and good dynamic response,is proposed.And the use of synchronous rectification and soft-switching technology improves the efficiency of multi-output DC-DC converter.After analyzing the feasibility,working principle and soft-switching characteristics of the topology,the small-signal model of the topology is deduced by means of the average switching model.Then,according to performance requirements,5V/6A,3.3V/10 A,1.8V/10 A,the controllers of multi-output DC-DC converter are designed with voltage mode and average current mode respectively.And the criterion of averaging current mode to avoid subharmonic oscillation in the leading edge modulation mode is given.Finally,the validity of the theoretical analysis and the rationality of the parameters are verified by simulation and an experimental prototype.