一种基于自适应非均匀网格的晶体管表格模型

An Adaptive Nonuniform-Grid-Based Table Model for Transistors

提出一种通过自适应建立非均匀网格来构建晶体管表格近似模型的方法,该方法借助哈希映射和辅助查找表能快速查找表格中的待计算点.自适应的非均匀网格构建方法继承了基于树状模型近似方法自适应划分的优势,克服了树状结构中单元查找速度慢的问题.通过在非均匀网格上进行三次Hermite样条插值来保证表格模型计算的连续性和平滑性,克服了树状结构模型中导数不连续导致收敛困难的问题.实验结果表明该方法可显著加速仿真过程中晶体管模型计算过程,以可接受的内存需求有效缩短电路仿真中瞬态分析的时间并获得较高的精度.

By adaptively building a structured nonuniform grid, a method of setting up a table-based approximatetransistor rncel is proposed. A hash mapping rule and auxiliary look-up tables are established whereby the point to beevaluated can be efficiently locate3. This method inherits the advantage of adaptive space partition feature from tree-basedel approximation method and overcomes the problem of inefficient searching for ceils in tree-based structure.Furthermore, the continuity and smoothness of table-based model evaluation are preserved by using the cubic Hermitespline interpolation on the structured nonuniform grid. As a result, the convergence problem caused by the discontinuousderivatives existing in tree-based model is circumvented. Experimental results show that the proposed methods cansignificantly accelerate the model evaluation of trahsistors and effectively reduce the transient analysis time with relativelyhigh accuracy and acceptable memory requirement during circuit simulation.