Design Of High Efficiency Boost Converter

With the development of technology and the maturity of semiconductor technology,the size and application of electronic products are increasing,and the demand for power supply is also increasing.Among them,the DC-DC converter,as a member of the power conversion chip,uses high-frequency switching to transmit energy through the energystored component.Ideally,the switching has no voltage dropout at on state,so there is no switching loss,so it can achieve higher efficiency than LDO.Among them,the current mode DC-DC switching converter is widely used because of its simple compensation network,fast response speed,and easy control of input and output current.This thesis first discusses the advantages of the current control mode by comparing the difference of each control mode and topology.Then,the power stage circuit,the outer voltage loop,and the inner current loop are linearized and modeled respectively in the constant voltage mode and the constant current mode.The modeling results will be shown through Matlab,and compared with the simulation result in SIMPLIS.The result shows the only differences is in low-frequency gain and frequency response above 1/2 switching frequency,which proves the validity of the modeling in this thesis.Then through the research on the loop stability in low-frequency and high-frequency of the modeling results,the corresponding compensation strategy is formulated,and the corresponding compensation parameters are obtained.In this thesis,based on 0.18μm BCD process,according to the compensation strategy above,a high-efficiency high-voltage boost converter with integrated power switch is designed.The proposed boost converter adopts fixed-frequency peak current mode architecture.The maximum input voltage and output voltage is 60V,and the maximum inductor current is 3.5A.Various fault protection functions are designed,and the converter can switch between constant voltage mode and constant current mode.The simulation results show that the converter can operate in the constant voltage or constant current mode with fast transient response.And the under-voltage lockout,soft start function guarantee the robustness of the proposed converter.The load regulation of the converter is 0.29%/A when input voltage of 12V and output voltage of 32V,and 0.47%/A under the large boost ratio of 6V input voltage and 20V output voltage.The converter has a linear regulation of 0.016%at 32V output voltage and meets the minimum input voltage requirement of 4.7V.When the input voltage is 12V,the output voltage is 32V,and the 22μH inductor is used,consider the external parasitic parameters,the peak conversion efficiency is up to 97%.