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.