Research Of Modeling Technology In Analog Circuit Simulation

With the rapid development of the microelectronics industry, the field of electronic products involved in continues to expand, it has been deeply into all aspects of national defense, health care, education and public life and bring a lot of convenience to our lives, which has been a widespread concern industry. The relatively industry has also been rapidly developed, one of them is the circuit simulation and circuit fault diagnosis technology. It provides reliability of electronic products, rapid response to fault equipment, and diagnostics for complex circuit simulation, which has become a very important research topic. The simulation provides the data dictionary for the diagnosis, the accuracy of the simulation result depends on the simulation algorithm and the accuracy of model. The simulation algorithm is relatively mature, and variety number of electronic devices is large and still growing, which determines the device modeling is also improving and perfecting.In the thesis, Ngspice is tread as the simulation engine, focus on completing building simulation environment, device modeling and fault simulation modeling. Firstly, the development and status of circuit simulation and device modeling theoretical studies is described. The principles of SPICE simulation is researched, focusing on the Newton-Raphson iterative algorithm, Euler equations and Matrix LU decomposition algorithm. The device module of simulation engine has been deeply analyzed.Then the theory of status quo device modeling and fault modeling is introduced, analysis focused on the characteristics of the three components of the model and the actual situation and needs of the project, use a macro model modeling, block modeling ideas for each respectively, to achieve sub-module, and then each sub-module integration, the establishment AGC circuit model. Pspice simulation simultaneously in synchronization by comparing two sets of data, to verify the correctness of the model.Finally, Using schematic drawing method, connection method of model and device graphics, simulation engine invocation mechanism, the existing device models and graphics library, compiled circuit technology and vs2010as a tool to achieve the graphical schematic capture, save and read. It can compile and simulate circuit, and provides an interface for the simulation software extensions.