Design Of Buck Type DC-DC Converter Based On 0.18 μm SOI Process

As an important power supply module in aerospace electronic system,the anti-radiation capability of DC-DC converter is very important to the reliability of equipment.It is of great significance to study the hardening technology of DC-DC converter in irradiation environment and improve its reliability.Based on 0.18μm SOI technology,this paper designs a Buck type DC-DC converter which can be used in outer space.The key circuits of DC-DC converter,such as bandgap reference voltage source,linear voltage regulator,protection circuit,error amplifier and PWM comparator,are studied and implemented.The Single-event transients effect of bandgap reference voltage source in the power supply module of DC-DC converter is studied and reinforced.The whole DC-DC converter is mainly composed of 5 circuit modules.The bandgap reference voltage source provides voltage reference and bias current for the whole system.The linear voltage regulator provides the supply voltage to the digital logic module in the system,which reduces unnecessary power consumption.Error amplifier and PWM comparator are important modules to realize the function.After adding compensation network in the loop,stable output can be achieved.The protection module is composed of under-voltage protector and over-temperature protection module,which can prolong the service life of the chip.This design optimizes the error amplifier,introduces negative feedback into the circuit,reduces the gain bandwidth of the whole system by reducing the equivalent transconductance,and improves its stability;and the sensitive node of the bandgap reference voltage source is injected with a double exponential current source to simulate the Single-event transients effect,and a current compensation circuit with symmetrical structure is proposed.When the circuit is affected by the Single-event transients effect and the output voltage suddenly increases or decreases,the comparator outputs high and low level to control the opening of the MOS tube,so as to ensure the stability of the output voltage to the maximum extent.Finally,emulator is used to verify the DC-DC converter.The power supply voltage is 5 V,the frequency range of the input signal is 0.75 MHz to 2.25 MHz,the input voltage is 2.5 V to 6 V,the output voltage is 0.6 to 4 V,and the output current is0 to 8 A.The maximum efficiency can reach 92%,The anti-irradiation index was SET LET_TH≥37 Me V·cm²/mg.