Radiation Resistant Circuit Design Based On RISC-V IP Core

In recent years,the blockade of my country’s integrated circuits by foreign countries has become more and more serious,and it is imminent to choose an open source instruction set architecture for application in aerospace equipment.The RISC-V architecture is an open-source architecture that is concise,efficient,and modular,similar to the requirements for integrated circuits required on aerospace equipment.With the development of integrated circuit processes,integrated circuits working in space environments are more susceptible to radiation effects(single event latching effect,single event upset effect,single event transient effect,total dose effect,etc.),which can lead to errors in minor cases and device failure in severe cases.Improving the radiation resistance of RISC-V-based integrated circuits has become a hot research topic in recent years.This project is based on a RISC-V processor with a two-stage pipeline architecture for radiation-resistant circuit research.According to the characteristics of low power consumption,high efficiency and small area of RISC-V processor,the appropriate anti-radiation technology is selected.For the core module and memory module in the sensitive module,and the trigger and storage unit in the sensitive unit,the radiation resistance design is carried out respectively,and the radiation resistance circuit design of the processor is completed in a hierarchical manner.The main work of this paper is:(1)For the system-level module,this paper adopts a modified RTL code to implement an error detection circuit at the output of the sensitive module,which solves the problem of single event effect causing errors to pass between system-level modules.The processor kernel module adopts the dual-core lock-step technology,using the dual-core redundancy and comparison module to implement an error detection mechanism at the top level of the kernel,which flushes the pipeline in case of kernel output errors to achieve processor restart.The memory module adopts redundant coding technology,and the memory read/write operation is coded and decoded by the extended Hamming code to achieve the function of"check two and correct one",which effectively reduces the probability of memory error transmission.After the code modification is completed,the overall circuit is simulated with the instruction set,and the simulation results show that the circuit functions the same as before the radiation resistant design.(2)For the circuit cell module,this paper adopts the redundant structure to modify the circuit cell structure and solve the problem of poor resistance to single event effect of the circuit cell.Using the device-circuit co-simulation method,the particle incidence simulation is carried out on the inverter device model,and the drain current after the particle incidence is obtained as a fault injection current model.This paper designs Dual Interlocked Storage Cell(DICE)-type flip-flop with redundant delay filtering structure(RDF)and DICE-type Static Random Access Memory(SRAM)cell with delayed filtering structure,analyzes their anti-radiation mechanism,and simulates the basic cell and the improved anti-radiation cell with fault injection current model By analyzing the simulation results,it shows that the improved unit has good radiation resistance.Finally,a single-particle flip-flop test was conducted on the flip-flop 1000-level chain century circuit composed of the flip-flop,and the experimental results showed that the flip-flop hardly flips at a ion linear energy transfer(LET)value of 65.6 Me V.cm~2/mg and a proton LET value of 100 Me V.cm~2/mg.(3)Using the cell library containing the radiation-resistant flip-flop to physically synthesize the circuit after the system-level radiation-resistant design,the synthesized area is1612932μm~2,the operating frequency is 66.7MHz,and the power consumption is164.9034m W,and the results meet the performance index of the radiation-resistant circuit.The post-simulation of the overall system after synthesis is carried out,and the simulation functions of the peripherals such as RAM,QSPI,GPIO and UART are correct to show that the system function meets the expectations,which shows the correctness and effectiveness of the design method of the anti-radiation circuit adopted in this paper.