The Design And Analysis Of Single Inductor Multiplexed Output DC-DC BOOST Converter Based On Standard CMOS Process

With the development of portable electronic products market,the demand for power management IC especially switching power supply IC is bigger and bigger.Meanwhile,because the portable electronic products are moving toward lower voltage,lower power and smaller systems,the performance requirements of power management IC such as area and convert efficiency become higher.The traditional single inductor single output(SISO)DC-DC converter cannot meet the power requirement of the whole SOC due to the limited output number.And using several SISO DC-DC converters will increase the area of SOC significantly,while the resulting EMI problem cannot be ignored.To solve this problem,in recent years some literatures proposed to realize multiplexed output by using single inductor.This paper presents a single inductor double output(SIDO)DC-DC BOOST converter with low cross regulation and low start-up voltage.Firstly,this paper analyzes the basic theory of DC-DC BOOST converters,introducing and summarizing the traditional control mode,then on this basis designing the control mode of the SIDO converter in this paper.Afterwards,the small signal model of the control loop and the design of compensation loop are studied and analysed in the paper.Then,the design of module circuits is discussed in detail such as the error amplifier with four inputs,the current sensing circuit,the circuit of generating dead time and the bandgap reference.Besides,this paper briefly talks about the layout design of the SIDO converter and discusses the details that need to be paid attention to.Since many problems need to solve in the issue of designing the SIDO converter proposed in this paper such as start-up problem,shutdown problem and cross regulation problem,several corresponding module circuits are proposed to improve or to solve the problem mentioned above,which are expounded in detail in the corresponding sections.Finally,based on SMIC 0.18μm Mixed signals CMOS technology platform,this paper completes the simulation of the presented SIDO converter The simulation results show that the presented SIDO converter can launch when the input voltage is 600 m V,moreover,the start or shutdown function of the proposed converter works normally in different load cases.Besides,the cross voltage regulation drops to 0.12 m V/m A and 0.06 m V/m A respectively by adopting cross regulation suppression circuit.What’s more,the conversion efficiency reaches to around 94% and 91% when the input voltage is 1V and 0.7V,respectively.The simulation results verify that the SIDO DC-DC BOOST converter designed in this paper meets the design objective,which is suitable for low input voltage,low cross regulation voltage applications.