Design Of The Key Module For A Synchronous Buck DC-DC Switching Power Regulator

ABSTRACTWith the explosive growth of portable electronic products in recent years,the market for switching power management chips directly related to them has also grown rapidly.The demand for switching power management chips is also increasing,including higher efficiency,lower power consumption,higher reliability and higher integration.Aiming at the development of current switching power management chip technology,this article designs a synchronous buck DC-DC regulator based on pulse width modulation(PWM)peak current control mode.According to the principle and working characteristics of PWM switching power supply,the design,simulation and layout of the main circuit modules are reasonably completed.The main contents of the article include:1.Briefly introduce the types of switching power supplies,the development status at home and abroad,and their development trends;2.Analyzed the structure and basic principle of the switching power supply,including the basic topology of the switching power supply and the control mode of the switching power supply;3.Completed the design and simulation of the key circuit modules in the voltage regulator,including: startup module,voltage reference source module,current reference source module,low dropout linear regulator(Low dropout regulator,LDO)module,error amplifier(Error Amplifier,EA)module,current comparator(Current comparator,ICOMP)module,phase-locked loop module,undervoltage protection circuit module,etc.4.The circuit layout of the key modules is given;5.Summarize the full text work,point out the lack of design,and put forward expectations for future work.This paper is based on the 0.35?m BCD process for circuit design and the circuit simulation using the Cadence Spectre tool.The simulation results verify the feasibility of the design and the correctness of the theoretical analysis.The designed DC-DC regulator has an input voltage range of 2.375V-5.5V,an operating frequency of 1.5MHz,and a lockable frequency range of 0.75 MHz to 2.25 MHz.At the same time,the power switch tube and the synchronous rectifier tube are integrated internally to simplify the size of the peripheral circuit structure and the peripheralcircuit,and improve the conversion efficiency of the circuit.The regulator is suitable for applications such as single Li-Ion batteries,point-of-load power supplies,portable electronics,and battery-powered devices.