Design Of Low Voltage And Large Current Load DC-DC Converter With Radiation Immune

DC-DC converter is an important and indispensable component in most electronic devices.With the development of space industry in our country,the aerospace level DC-DC converter is proposed more pressing demand.The system requests DC-DC convertor has the characteristics of high efficiency,large load current,high line regulation,high load regulation,fast transient response,low noise,low ripple and radiation immune,the traditional DC-DC convertor has been unable to meet the system requirement.The aerospace level DC-DC convertor products are rare at present that need the strong support from design,process and package platform,it is the development direction of power management products.This thesis presents a low voltage large load current DC-DC convertor with radiation immune,it has the characteristics of wide working voltage range,large load current,high line regulation,high load regulation and high peak efficiency.This DC-DC convertor integrates with error amplifier,reference circuit,slope compensation circuit,current comparator,charge pump,oscillator,level shifter circuit and power MOSFET in a simple peripheral circuit.This DC-DC is a Buck convertor uses peak current-control method PWM(Pulse Width Modulation)so that it can response fast in transient.In the base of the traditional circuit structure,a novel error amplifier circuit structure is adopted to improve the transient response of the DC-DC convertor;a high PSRR(Power Supply Ripple Rejection)reference circuit is adopted to improve the DC-DC convertor's line regulation and load regulation also.A novel LDO circuit structure is also designed in this DC-DC convertor.Not only a method of layout design which against Total Dose radiation but also SEL(Single Event Latchup)have been presented in this thesis.The DC-DC convertor in this thesis is designed in 0.18?m BCD(Bipolar CMOS DMOS)process.Firstly,the DC-DC convertor schematic is designed and simulated based on this process model in Cadence software,confirmed that the simulation results meet the design requirements;Secondly,layout design is completed,Calibre is used to do the Design Rule Check and Layout VS Schematic Check,The chip size is2.4mm×5.3mm;thirdly,the design is taped out and the package is completed;Finally,the circuit is tested and radiation baseline experiment is completed.The test results show that the DC-DC convertor's working voltage range is fro m3.0V to 5.5V,load current ability is 3A,line regulation is less than 0.1%,load regulation is less than 0.5%,switching frequency range is 100kHz~1000kHz,Total Dose radiation immune is 100kRad(Si),Single Event Latchup immune is LET?85MeV-cm~2/mg,meet the design requirement.