组合电路故障模拟的一种新方法

A New Fault Simulation Approach to Combinational Circuits

本文提出组合电路故障模拟的一种新方法。对一个给定的输入向量t,除第一遍真值模拟是从电路的初级输入到初级输出进行计算外,故障模拟是从电路的初级输出到初级输入逐级进行表达式运算,由得到的表达式可以判断t能否检测电路中任何一条引线上的s—a—0或s—a—1单故障。本文还介绍了本算法和临界路径跟踪法相结合的一种算法,简化了临界路径跟踪法中对扇出源临界性的处理过程。

A new fault simulation approach to combinational circuits is proposed in this paper. For a given input vector, the true-value simulation, which isused to compute signal values of each line, is performed from primar-y inputs(PI)towards primary output ( PO ) as usual, but the fault simulation is done byexpression operation in the descending order of logic level from PO to PI. Whetherit detects the single fault s-a-0 or s-a-1 on every line can be decided from theexpression. An algorithm that combines this approach with critical path tracing ( CPT ) is also introduced and jt simplifies the processing procedure of the criti-cality computing of fanout stems in CPT.