Fault Detection and Diagnosis for Mixed-Signal Circuits Using Wavelet Based Transient Current Analysis

由于晶体管的固有泄漏随着技术的扩展而增加，静态电流 (IDDQ) 测试的有效性显着降低。基于瞬态电流 (IDD) 的测试经常被引用和研究，作为数字 CMOS 电路中 IDDQ 测试的替代和/或补充。虽然 IDD 测试在数字和模拟电路故障检测方面的潜力已经被证实，但目前还没有使用 IDD 分析进行故障诊断的有效方法。我们提出了一种利用小波变换进行 IDD 波形分析的数字 CMOS 电路故障检测和诊断的新型集成方法。我们使用小波变换在时域和频域上分解 IDD 波形。 IDD 信号的时频分辨率有助于我们检测和定位故障。 8 位 ALU 上的初步实验结果表明，考虑到过程变化和测量噪声的影响等实际问题，基于小波的 IDD 分析具有有效检测和定位故障的潜力。 瞬态电流 (IDD) 分析对于模拟电路的缺陷导向测试也很有效。我们观察到小波变换提供了一种分析 IDD 以进行模拟电路故障检测的有效方法。小波同时解析时域和频域事件的特性以及比傅立叶分析更好的子带特性，使其成为 IDD 分析的有效工具。此外，小波变换可以轻松适应不同电路的电流波形。我们观察到，对于相同数量的频谱分量，对于灾难性故障和参数故障，模拟电路中基于小波的故障检测的灵敏度远高于傅里叶或时域分析。 基准电路的初步实验结果表明，对于参数故障，基于小波的方法平均比 DFT 灵敏 25 倍，并且可以被认为是测量硬件噪声和过程变化中模拟故障检测的有前途的替代方案。在拟议的研究中，我们将开发一种使用基于小波的混合信号电路瞬态电流分析的集成故障检测和诊断方法。我们将在国内和国际会议上展示我们的研究成果。国际会议包括（2003 年 12 月在澳门举行的国际 CAD 和 CG 会议，以及 2005 年在澳门举行的 CAD 和 CG 国际会议；在欧洲举行的 IEEE 设计和测试）。

As intrinsic leakage in transistor increases with technology scaling the effectiveness of quiescent current (IDDQ) testing reduces significantly. Transient current (IDD) based testing has been often cited and investigated as an alternative and/or supplement to IDDQ testing in Digital CMOS circuits. While the potential of IDD testing for fault detection has been established for digital and analog circuits, there is no known efficient method for fault diagnosis using IDD analysis. We propose a novel integrated method for fault detection and diagnosis in digital CMOS circuits using IDD waveform analysis using wavelet transform. We use wavelet transform to decompose the IDD waveform in both time and frequency domain. The time-frequency resolution of the IDD signal helps us detect as well as localize faults. Initial experimental results on an 8-bit ALU show that wavelet based IDD analysis has the potential to efficiently detect and localize faults considering practical issues like effect of process variation and measurement noise. Transient current (IDD) analysis can also be effective for defect oriented testing of analog circuits. We observe that wavelet transform renders an efficient way for analyzing IDD for fault detection in analog circuits. The property of wavelet for resolving events in both time and frequency domain simultaneously and the property of better sub-banding than Fourier analysis, makes it a effective tool for IDD analysis. Moreover wavelet transform can be easily adapted to current waveforms from different circuits. We have observed that for equivalent number of spectral components, sensitivity of wavelet based fault detection in analog circuits is much higher than fourier or time-domain analysis for both catastrophic and parametric faults. Initial experimental results on a benchmark circuit show that wavelet based method is on average 25 times more sensitive than DFT for parametric faults and can be considered as a promising alternative for analog fault detection amidst measurement hardware noise and process variation. In the proposed research we will develop an integrated fault detection and diagnosis methodology using wavelet based transient current analysis for mixed-signal circuits.We will present the results of our research in domestic and international conferences. International conferences include (International Conference on CAD and CG in Macau, December 2003, and International Conference on CAD and CG 2005; IEEE Design and Test in Europe).