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H.-C. Pan

Bio: H.-C. Pan is an academic researcher from National Taiwan University. The author has contributed to research in topics: Automatic test pattern generation & Scan chain. The author has an hindex of 2, co-authored 2 publications receiving 26 citations.

Papers
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Proceedings ArticleDOI
18 Jan 2010
TL;DR: In this article, a new weight assignment scheme for logic switching activity was proposed, which enhances the IR-drop assessment capability of the existing weighted switching activity (WSA) model by including the power grid network structure information.
Abstract: For two-pattern at-speed scan testing, the excessive power supply noise at the launch cycle may cause the circuit under test to malfunction, leading to yield loss. This paper proposes a new weight assignment scheme for logic switching activity; it enhances the IR-drop assessment capability of the existing weighted switching activity (WSA) model. By including the power grid network structure information, the proposed weight assignment better reflects the regional IR-drop impact of each switching event. For ATPG, such comprehensive information is crucial in determining whether a switching event burdens the IR-drop effect. Simulation results show that, compared with previous weight assignment schemes, the estimated regional IR-drop profiles better correlate with those generated by commercial tools.

21 citations

Proceedings ArticleDOI
07 Nov 2010
TL;DR: This paper presents a scalable implementation methodology for quantifying the IR-drop effects of a set of switching cells and an example of its application to guide power-safe scan pattern generation is illustrated.
Abstract: Analysis of power grid IR-drop during scan test application has drawn growing attention because excessive IR-drop may cause a functionally correct device to fail at-speed testing. The analysis is challenging since the power grid IR-drop profile depends on not only the switching cells locations but also the power grid structure. This paper presents a scalable implementation methodology for quantifying the IR-drop effects of a set of switching cells. An example of its application to guide power-safe scan pattern generation is illustrated. The scalability and effectiveness of the proposed quantitative measure is evaluated with a 130 nm industrial design with 800 K cells.

5 citations


Cited by
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Proceedings ArticleDOI
29 Apr 2013
TL;DR: A simulation-based X'Filling method, Bit-Flip, is proposed to maximize the power supply noise during PKLPG test and demonstrates that the method can significantly increase effective WSA while limiting the fill rate.
Abstract: Pseudo functional K Longest Path Per Gate (KLPG) test (PKLPG) is proposed to generate delay tests that test the longest paths while having power supply noise similar to that seen during normal functional operation. Our experimental results show that PKLPG is more vulnerable to under-testing than traditional two-cycle transition fault test. In this work, a simulation-based X'Filling method, Bit-Flip, is proposed to maximize the power supply noise during PKLPG test. Given a set of partially-specified scan patterns, random filling is done and then an iterative procedure is invoked to flip some of the filled bits, to increase the effective weighted switching activity (WSA). Experimental results on both compacted and uncompacted test patterns are presented. The results demonstrate that our method can significantly increase effective WSA while limiting the fill rate.

23 citations

Journal ArticleDOI
TL;DR: The proposed DfT support enables a design partitioning approach, where any given set of patterns, generated in a power-unaware manner, can be utilized to test the design regions one at a time, reducing both launch and capture power in a design-flow-compatible manner.
Abstract: At-speed or even faster-than-at-speed testing of VLSI circuits aims for high-quality screening of the circuits by targeting performance-related faults. On one hand, a compact test set with highly effective patterns, each detecting multiple delay faults, is desirable for lower test costs. On the other hand, such patterns increase switching activity during launch and capture operations. Patterns optimized for quality and cost may thus end up violating peak-power constraints, resulting in yield loss, while pattern generation under low switching activity constraints may lead to loss in test quality and/or pattern count inflation. In this paper, we propose design for testability (DfT) support for enabling the use of a set of patterns optimized for cost and quality as is, yet in a low power manner; we develop three different DfT mechanisms, one for launch-off shift, one for launch-off capture, and one for mixed at-speed testing. The proposed DfT support enables a design partitioning approach, where any given set of patterns, generated in a power-unaware manner, can be utilized to test the design regions one at a time, reducing both launch and capture power in a design-flow-compatible manner. This way, the test pattern count and quality of the optimized test set can be preserved, while lowering the launch/capture power.

20 citations

Proceedings ArticleDOI
19 Nov 2012
TL;DR: Experimental results on larger ISCAS'89, ITC'99, and IWLS'05 benchmark circuits show that the proposed scan cell design lowers capture power consumptions with reasonable CPU times and test set inflation.
Abstract: Shift and capture power management has become indispensable for modern complex low-power designs. Excessive shift power increases test application time and may jeopardize the shift operation correctness, excessive capture power during at-speed scan testing may lead to yield loss. This paper proposes a scan cell design which isolates scan cells output transitions in both shift and capture modes. Experimental results on larger ISCAS'89, ITC'99, and IWLS'05 benchmark circuits show that the proposed scan cell design lowers capture power consumptions with reasonable CPU times and test set inflation.

14 citations

Proceedings ArticleDOI
Irith Pomeranz1
12 Dec 2011
TL;DR: A procedure is described that generates broadside test sets with bounded switching activity during fast functional capture cycles based on the maximum switching activity of a functional broadsideTest set, targeting transition faults in full-scan circuits.
Abstract: For most purposes, it is sufficient for a low-power test set to ensure that the power dissipation during test application will not exceed that possible during functional operation. This is guaranteed for the fast functional capture cycles of functional broadside tests. This paper describes a procedure that generates broadside test sets with bounded switching activity during fast functional capture cycles based on the maximum switching activity of a functional broadside test set, targeting transition faults in full-scan circuits. The procedure first generates a compact functional broadside test set. It then extends the test set in steps in order to increase its fault coverage to that of an arbitrary broadside test set (a test set that includes non-functional broadside tests). During these steps, the maximum switching activity of the functional broadside test set is used for bounding the switching activity.

12 citations

Journal ArticleDOI
TL;DR: A novel technique that modifies automatic test pattern generation test patterns to reduce time-averaged IR drop of a test pattern with almost no fault coverage loss and no test pattern inflation is presented.
Abstract: This paper presents a novel technique that modifies automatic test pattern generation test patterns to reduce time-averaged IR drop of a test pattern. We propose a fast average IR drop estimation, which is very close to the time-averaged IR drop of time-consuming transient simulation ( $R^{2} =0.99$ ). We calculate the contribution of every node to these nodes inside IR-drop hotspot so that we can effectively modify only a few don’t care bits in the test patterns to reduce IR drop. The experimental results show that our technique successively reduces time-averaged IR drop by 10% with almost no fault coverage loss and no test pattern inflation.

9 citations