Research On Analog Circuit Simulation Technology Based On Wave Digital Filter And FPGA

Circuit simulation has become an indispensable part of modern electronic circuit design process,in order to ensure a successful circuit design and mitigate costly and potentially dangerous design flaws,careful planning and evaluation must occur at every stage of the process.Circuit simulation provides a cost-effective and efficient method for identifying faults before moving to the more expensive and time-consuming prototyping stage.Therefor the best design processes include a good mixture of simulation and prototyping.But Software simulation of analog and mixed-signal circuits often takes a long computing time,and such long time may prevent Monte Carlo simulations,which becomes increasingly necessary for modern system integration.While the hardware base algorithm system has significant advantage on processing speed,it is important to develop a FPGA-based circuit simulation / emulation system.This paper proposed a WDF-FPGA simulation system,which is based on wave digital filter(WDF)theory.For solving the key technical problems on system's design and realization,following contributions and innovations are archieved during research.1.In this paper,an optimizing methodology for WDF equivalent circuit is proposed.This binary tree based method could simplifiy simulation system and improve system performance on speed.WDF binary tree representation has a clear and intuitive structure,solving low expressing efficiency issue in traditional WDF topology.The shape of this tree directly indicates essential information of WDF equivalent circuit,such as module parallelism and the longest path.Moreover,this paper presents optimizing methology for WDF binary tree,which could reduce processing stpes in each simulating cycle,improve the overall performance of simulation.2.This paper proposes a new design for WDF module,which is based on nonlinear look-up-table(LUT).This design solves the complexity issue in WDF module construction for nonlinear ciruit element,also takes adavantage of FPGA's feature to accelerate simulation.On the other hand,the nonlinear LUT based WDF module is compatible with WDF binary tree topology,makes system optimization easiler.Futuremore,this paper presents MOSFET WDF equivalent with aformentioned design,and validates this equivalent by successfully simulating two corresponding nonlinear analog circuit.The simulation results prove the nonlinear LUT based WDF module design is feasible and suitable for FPGA implementation,indicates this design method could be foundation for realizing WDF-FPGA simulation system.3.Based on above research achievements,this paper presents and implements WDF and FPGA based circuit simulation/emulation system.This WDF-FPGA system is composed by three functional areas,including variable converting units for solving K-W domain crossing problem.And four specially designed adaptors are presented to divide simulation into incident and reflection process.By optimizing those two process separately,WDF-FPGA system could have the most suitable topology with the best parallelism and shortest incidentreflection path.The feasibility of WDF-FPGA system is validated by linear and nonlinear analog circuit simulaitons,and validation results confirm relevant essential technical problems have been solved.