Design Of Delay-Locked Loop And Research Of Radiation Hardened Key Circuits

With the development of integrated circuits and aerospace industry,aerospace electronic systems have more stringent requirements for internal high-frequency clock signals.Delay-Locked Loops(DLL)working in an irradiated environment are easily bombarded by heavy particles with ultra-high energy,so which trigger Single Event Transient(SET)and make the DLL lose lock and false lock.Based on those,a radiation harden delay-locked loop is designed in this thesis.The main contents including:Firstly,based on analyzing the basic structure of DLL,this thesis discusses the influence of radiation effects for the circuit and discusses the small signal model and lock range of the DLL system.According to the index requirements,the relevant important parameters of the system are determined.Secondly,these function module circuits of DLL are designed in this thesis,which includes phase detector,charge pump,voltage-controlled delay line and so on.And,the designed charge pump circuit broadens the dynamic range and reduces current mismatch by adopting operational amplifier clamping technology and low-voltage current compensation technology.When the charge pump current is 42μA,the error of the charge and discharge current is less than 1% in the output voltage range from 0.25 V to 1.05 V.The designed voltage-controlled delay unit improves the uniformity of the output clock by adopting a multiplexed differential delay unit.Simulation results show that the designed DLL has a lock frequency range of 700MHz～1GHz,lock time of less than 1μs,static phase error of less than 50 ps and clock jitter of less than 10 ps.Finally,based on the analysis of the SET transient response for the DLL,a radiation harden charge pump is designed by adopting the current complementary technology,and a radiation harden phase detector is designed by the three-mode redundancy technology,.a radiation harden low dropout linear regulator is designed by adopting the current effluent technology and Temporal-filter technology.Based on the designed sub-cirucits of DLL,a radiation harden delay-locked loop is designed in this thesis.Simulation results show that the lock recovery time is shortened by 44.3%,the maximum disturbance of Vctrl is reduced by 91.5%,and the maximum phase shift is reduced by 84.3%.