| In recent years,DC-DC converter is widely used in standby power supply of server equipment,vehicle control system and PC power supply.How to extend the working time of battery power supply under the same battery capacity becomes the research direction.At present,the main methods are:1)increasing the input voltage range of DC-DC converter can make the system continue to work under the condition of lower input voltage;2)improving the efficiency of DC-DC converter.In addition,the application of system has higher and higher requirements for power supply,and the dynamic response and requirements of ripple for DC-DC converter output voltage are also higher and higher.Based on these requirements for application,this paper proposes a non-inverting DC-DC buck-boost converter with wide input voltage range,high efficiency,stable output voltage ripple and smooth transition during mode switching.The hysteresis control is added between the modes to avoid the deterioration of output voltage ripple caused by frequent switching between the modes.Compared with the traditional inverting buck-boost converter,the input and output voltage of the non-inverting DC-DC buck-boost converter proposed in this paper are in the same phase,so there is no need to generate negative reference voltage inside the chip,and there is no need to add inverter between the converter and the application circuit,which can effectively increase the application range of buck-boost converter.At the same time,compared with the traditional non-inverting DC-DC buck-boost converter,the converter proposed in this paper adopts three mode control,which can segment control according to the input voltage value,reduce the frequency of switching action,thus improving the efficiency of the converter in the whole input range.The proposed converter only needs one PWM comparator and one error amplifier,which can simplify the architecture of the converter.The proposed converter can reduce the dynamic interference and stabilize the output voltage by adding DC offset voltage module.Firstly,This paper introduces the basic principle of the traditional non-inverting DC-DC buck-boost converter.On this basis,the basic structure of the three modes high efficiency non-inverting DC-DC buck-boost converter is put forward,and the working mode,modulation mode and control mode of the high efficiency synchronous 4 transistor DC-DC boost voltage converter are analyzed.Then,the key problems of the high-efficiency non-inverting DC-DC buck-boost converter are analyzed,the basic structure and loop analysis of the converter are given,and various parameters and typical application circuits of the converter in typical applications are determined.In this paper,the 0.18 BCD process is used to realize the circuit design,and Cadence Spectre simulation tool is used to verify the module circuit and system circuit.The results show that the converter can transition smoothly and the output voltage ripple is stable during mode switching.Design requirements:input voltage 2.7v-36v,output voltage 3.3v-40v,maximum load current 2A,output voltage ripple?1%Vou t,output voltage jump caused by load step?10%Vout,switch frequency 1MHz. |
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