Design And Implementation Of Mixed-signal Circuit Simulation Software Based On Ngspice Engine

In recent years,due to the rapid development of microelectronic technology industry,many related electronic industry research has also developed rapidly,among which circuit simulation research has gradually become a hot subject.Traditional circuit simulation is mainly divided into analog simulation and digital simulation.The two methods have completely different simulation algorithms and device representation.Analog circuit is simulated by solving the equations of the circuit,which processes continuous data;The digital circuit is simulated by time driven method,which deals with discrete state data.However,due to the deepening of the electronic industry,pure analog circuit or pure digital circuit can't meet people's requirements.More and more circuit designs are developing towards digital analog hybrid circuit.At present,there are several hybrid circuit simulation software on the market,but most of them are commercial software,which are expensive and not open.For example,saber simulator and ADMS simulator are simulators designed in local mode.They use a single engine to combine analog circuit design with digital circuit design,and realize the simulation of hybrid circuit by modeling the hybrid model and improving the algorithm.They support a variety of simulation languages and have enough accuracy,but they all have the problem of insufficient device model.Based on this,this paper studies,designs and implements an integrated digital analog hybrid circuit simulation software with ngspice as the simulation engine.This paper first introduces the development and current situation of circuit simulation analysis and digital analog hybrid simulation using computer,and then briefly expounds the design ideas,simulation tools and modeling language of relevant circuit simulation software,focusing on the basic principle and core algorithm of simulation of analog circuit,digital circuit and digital analog hybrid circuit.In the design of hybrid circuit simulation software based on ngspice simulation engine,there are three key problems: ngspice engine call management,digital simulation algorithm and mixed signal synchronization.This paper proposes an engine calling mechanism that encapsulates the ngspice engine as a dynamic link library for calling,designs the component library management module to model,package and store digital devices and digital analog hybrid devices,improves the synchronization algorithm module,and solves the synchronization problem in digital analog signal conversion.In order to verify the usability of the software,this paper simulates some typical digital analog hybrid circuits.The simulation results show that the simulation results are within the acceptable error,the software has good performance,innovation and popularization.