Design Of Low Quiescent Current PWM Boost DC-DC Converter Based On Current Mode

With the rapid development of communication technology and power electronics technology,switching converter has been widely used in portable electronics,military communication systems,medical equipment,vehicle electronics,aerospace and other fields.Switching converter also knowns as switching power supply,which is a highfrequency power conversion device.Its function is to convert a level of voltage into the voltage or current required by the user through different architecture,the input of the switching converter is mostly AC/DC power,and the output is mostly equipment that requires DC power.From the voltage conversion method,it can be divided into several topologies such as Boost,Buck or Buck-Boost.Compared with linear power supply,switching power supply have the advantages of low power,low area,and high efficiency.Based on these advantages,switching power supply has become the focus and hotspot in the field of power supply research,so it’s crucial to research on switching converter.This thesis implements a Boost DC-DC that can be used in alkaline batteries,button batteries,or lithium-ion battery power systems.When the input is higher than 1.8V,the output can reach 3～5V.This Boost DC-DC system includes modules such as current sampling,slope compensation,error amplifier,precharge and substrate potential selection,etc.The main content of the design is to complete the ideal model construction,realize the design and simulation of the transistor-level circuit,and achieve the back-end layout design and optimization.This design has both integrated precharge and soft-start functions,these two start-up buffers allow the output voltage to rise slowly in stages,which can avoid overcharge of the output voltage and inrush current.This thesis also proposes a substrate potential selection circuit,which makes the load stage and input stage fully separated when the converter is turned off,so this design has low quiescent current.This Boost DC-DC chip is implemented based on UMC 0.35μm CMOS process.When the input voltage is higher than 1.8V,the output voltage can reach 5V,and the output current can reach 500 m A.The switching frequency is 1.2MHz,and the quiescent current is 10.3μA.The die area is 2mm*3mm.