| In the aerospace environment,integrated circuits will be affected by radiation,which will make the normal function of the circuit cannot be realized.DC-DC converter plays a vital role in the power system of spacecraft,because it can provide a stable output voltage,so it plays an irreplaceable role in the whole system,its performance is related to the spacecraft internal electronic system can work reliably,so study the radiation effect on the mechanism of DC-DC converter,And the corresponding technical scheme of anti-radiation hardening is put forward,which has broad research prospect.Traditional radiation hardening schemes are mostly carried out at the process level and layout level.This method depends on the radiation resistance of the process itself to a large extent,which often brings the problem of high cost,and can not provide a good reliability evaluation in the initial circuit level design,and its operation is complex and inflexible.Aiming at the shortcomings of traditional anti-radiation hardening schemes,this paper analyzes the mechanism of total dose effect on circuits by starting with the circuit level total dose effect simulation method,and proposes a circuit level total dose radiation effect hardening circuit,which can realize the parallel work of adaptive total dose monitoring and hardening.The continuous real-time monitoring and synchronous hardening of the total dose effect suffered by the circuit are achieved.On this basis,a Buck-Boost type DC-DC switching power converter is designed to resist the total dose radiation effect.The core modules such as error amplifier module,band gap reference module and PWM comparator module are hardened.In this paper,the circuit is designed and verified by simulation based on 0.18 μ m BCD technology,and the layout design is completed.The simulation results show that the phenomenon of parameter drift in Buck-Boost converter under radiation is effectively improved by adding the total dose effect hardening circuit in this paper.At the radiation dose of 200 krad(Si),the gain of the error amplifier module decreases from 86.8dB under normal conditions to 70.1dB,and the gain drift rate is 19.2%.The output reference voltage of bandgap reference module shifts from 1.1978V to 1.2043V under normal conditions,and the reference voltage shift rate is 0.54%.The PWM comparator module generates a 5ns delay.The output voltage of the system will produce 54mV drift,and the drift rate is 2%.The load adjustment rate and linear adjustment rate increase from 0.062%/A and 0.023%/V to 0.509%/A and 0.319%/V respectively.Moreover,the conversion efficiency of the system decreases under different loads.Conversion efficiency decreased from 87.6%to 76.7%.The gain of the error amplifier module is compensated to 81.4dB and the gain drift rate is reduced to 6.2%after the total dose effect is added to strengthen the circuit.The reference voltage of the output band gap reference module is compensated to 1.1986V,and the drift rate of the reference voltage is reduced to 0.06%.The delay time of PWM comparator module is reduced to Ins,which reduces the delay time by 80%,and the above parameters perform well under PVT.For the hardening effect of system parameters,the output voltage drift is reduced to 4mV,the drift rate is reduced to 0.15%,and the load adjustment rate and linear adjustment rate are reduced from 0.191%/A and 0.093%/V respectively.Under the load of 600mA,the conversion efficiency is increased from 76.7%to 83.4%. |
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