一种动态电流测试产生方法的SPICE模拟验证

数字电路状态发生改变时,数字电路中的逻辑跳变直接影响电路中的动态电流.基于布尔过程的波形模拟器能够快速准确地对电路进行模拟,其结果既能反映电路的逻辑特性又能反映电路的定时特性.利用波形模拟器可以准确的了解电路中跳变的情况.本文利用波形模拟器改进并实现了一种基于逻辑跳变计数的动态电流测试方法.对于S208电路中的部分开路故障和延时故障,本文用该方法产生了一组测试结果,并利用SPICE软件对这些测试结果进行了模拟实验.模拟结果表明,对于某些故障,测试向量对能够使故障电路的动态电流和无故障电路的动态电流产生较大的差别.通过比较两者平均动态电流的大小,我们能够区分出故障电路和无故障电路.实验结果验证了本文中的动态电流测试产生方法的有效性和可行性.

The Validation of a Dynamic Power Supply Current Testing Method by SPICE

When a digital circuit switches states,logical changes in the circuit can directly influence the transient power supply current of the circuit.Waveform simulator based on Boolean process can simulate digital circuits precisely and efficiently.The result of the waveform simulator reflects not only the logic functions but also the timing behavior of a circuit.From the simulation results of this waveform simulator,we could get all the information about logical changes in a circuit.Based on this waveform simulator,the paper made some improvement on a dynamic current testing method based on counting logical changes and implemented it.For some open faults and delay faults injected in the S208 circuit,this method gave out some testing results.SPICE simulation experiments were done on the testing pairs generated by this method.Experimental results show that,for parts of the open defects and delay defects in the circuit,testing pairs generated by this method can arouse great difference between the transient power supply currents of the fault circuit and the fault free circuit.By comparing the average transient power supply currents,we could distinguish a fault circuit from a fault free circuit.All these results proved the feasibility and validation of this dynamic current testing method.