Research And Design Of High-power Boost Converter With Wide Conversion Range

Power management ICs(PMICs)have been widely used in digital products,household appliances,and communication equipment,to provide stable voltage for electronic systems.Among various PMICs,the Switched-Mode Power Converter has the advantages of high conversion efficiency,large output power,flexible adjustment of output voltage,as well as the wide application range.With the development of audio drive,solid-state lighting and other applications which require high output voltage and power,the research of boost switching power supply has become a hot topic in the academic and industrial circles.This thesis focuses on the research and design of high-power boost converter with wide conversion range,and a peak current-mode boost converter has been implemented.Starting from the basic principles,this thesis firstly introduces the topology,working mode of power stage and common loop control methods.Peak current control mode has been deeply studied,and the sub-harmonic oscillation phenomenon has been explained from both the large and small signal aspects.Aiming at solving the problem that,the boost converter was difficult to be stabilized under a wide voltage conversion ratio,detailed theoretical derivations and analysis have been carried out.Quality factor(hereinafter referred to as Q value)at the half switching frequency of the inner current loop is used to depict the poorer stability of the peak current mode system.An adaptive Q-value slope compensation manner has been proposed,which makes the compensation intensity following the duty cycle changes,leading to a stable system in a wide range of duty cycles.Then,system level design has been accomplished according to the target specifications,with the sequence of power stage,inner current loop,and finally outer voltage loop.Behavior-level simulation has been done with Simplis.Lastly,circuit level design has been accomplished as well.This design was under the SMIC 0.18μm BCD process,with the simulations in Cadence Spectre platform.The simulation results show that with the input voltage range of 2.8 V to 4.6 V,the output voltage range covers from 5 V to 40 V.The maximum voltage conversion ratio achieves 14,with the output power as high as 32 W.The ripples on output voltage are less than 100 m V.The peak efficiency is 93.1%,and the efficiency is higher than 88% across very wide load range.In a typical application of 8 V output voltage,the overshoot or undershoot is less than 5% of the output voltage,and the transient recovery time is not more than 70 us for a load step of 1 A.In addition,the load regulation is 2m V/A.