Implicit functional testing of switched current filter based on fault signatures

This article aims at defining an efficient test strategy for switched-current (SI) circuit testing. By checking the constructed signatures (impulse response samples) against the derived tolerance ranges, we can infer the correctness of the device under test without explicitly measuring the original performance parameters. We also describe a technique of mapping the tolerance ranges in the performance space to its associated tolerance ranges in the signature space (We call such a procedure implicit functional testing). Taking into account the specificity of SI circuit, catastrophic and parametric fault model for testing are constructed. A fifth order Butterworth low-pass filter and a sixth order Elliptic band-pass filter have been used as test benches to assess the effectiveness of the proposed technique. Test results demonstrate that high fault coverage can be achieved with low cost test equipments.