Deterministic Built-in Self-test Research Articles

Test Power Reduction through Reordering Algorithm Implementation and Advancements in BIST Architecture

Due to the reduction in transistor size, test engineers face a severe issue in power minimization. VLSI circuit's power dissipation has become a vital concern due to the switching activity of the Circuit Under Test (CUT). Switching activity is a significant factor in determining power consumption for CMOS VLSI circuits. In this paper, we formulate a distance estimation technique and reordering using the Tversky index. Here, the distance between the test vectors is calculated using the Tversky index with the formation of an adjacency matrix, and reordering is performed. The experimental results of the proposed method have been compared to different distance measures and existing techniques. It shows that the switching activity is reduced from 52.5% to 21.5%, and the average power reduction is from 42% to 14.6% when the distance is estimated on reordering using the Tversky index measure. Thus, the Tversky index distance measure performs better than the Hamming, gray, and Linear feedback shift register (LFSR) methods. Switching activity estimation for complex ISCAS circuits has been performed and compared with existing methods for superior performance. We have also developed a Built in Self-Test (BIST) for the C17 benchmark circuit, which uses the Tversky counter as a test pattern generator using the TANNER EDA tool. Thus, an efficient deterministic BIST for the C17 benchmark circuit was designed to detect all the stuck-at faults, and the same procedure can be used to create BIST for all CUT and precomputed test sets for real-time field testing.

Detection of Stuck Open and Short Fault in SRAM Based System

A novel scan-based Built-In Self-Test (BIST) architecture is designed with Low-Power (LP) for weighted pseudorandom test pattern generation (WPTPG) and reseeding, which is easy for the pseudorandom testing and deterministic BIST. The pseudorandom testing stage is designed by disabling a section of scan chains and in the deterministic BIST stage, the design-for-testability architecture is reorganize slightly while the linear-feedback shift register is kept short. The proposed technique of a BIST design for fault detection and fault diagnosis of Static-RAM (SRAM) based Field Programmable Gate Array (FPGAs) can detect the interconnect resources in the Configurable Logic Blocks (CLBs). The test pattern generator and output response analyzer are configured by CLBs in FPGAs. The testing procedure undergoes three major test blocks. They are Test Pattern Generator (TPG), Output Response Analyzer (ORA) and Block Under Test (BUT) in each test block. The stuck open and short faults are detected using SRAM based FPGA are observed in this paper.

Low-Power Scan-Based Built-In Self-Test Based on Weighted Pseudorandom Test Pattern Generation and Reseeding

A new low-power (LP) scan-based built-in self-test (BIST) technique is proposed based on weighted pseudorandom test pattern generation and reseeding. A new LP scan architecture is proposed, which supports both pseudorandom testing and deterministic BIST. During the pseudorandom testing phase, an LP weighted random test pattern generation scheme is proposed by disabling a part of scan chains. During the deterministic BIST phase, the design-for-testability architecture is modified slightly while the linear-feedback shift register is kept short. In both the cases, only a small number of scan chains are activated in a single cycle. Sufficient experimental results are presented to demonstrate the performance of the proposed LP BIST approach.

Deterministic built-in self-test using split linear feedback shift register reseeding for low-power testing

A new low-power testing methodology to reduce the excessive power dissipation associated with scan-based designs in the deterministic test pattern generated by linear feedback shift registers (LFSRs) in built-in self-test is proposed. This new method utilises two split LFSRs to reduce the amount of the switching activity. The original test cubes are partitioned into zero-set and one-set cubes according to specified bits in the test cubes, and the split LFSR generates a zero-set or one-set cube in the given test cube. In cases where the current scan shifting value is a do not care bit accounting for the output values of the LFSRs, the last value shifted into the scan chain is repeatedly shifted into the scan chain and no transition is produced. Experimental results for the largest ISCAS'89 benchmark circuits show that the proposed scheme can reduce the switching activity by 50% with little hardware overhead compared with previous schemes.

Deterministic Delay Fault BIST Using Adjacency Test Pattern Generation

In delay fault BIST (Built-In-Self-Test), an adjacency test pattern generation scheme effectively generates robust test patterns. The traditional adjacency test pattern generation schemes use LFSR to generate first patterns, and thus they cannot generate test patterns for circuits with more than 30 inputs with high fault coverage in a practical amount of time. This paper proposes a deterministic delay fault BIST method using adjacency test pattern generation. The proposed scheme uses first patterns generated by a deterministic algorithm based on the analysis of independent partial circuits on the circuit under test. Experiments show that test patterns generated by the proposed method have both high fault coverage and short test length, resulting in a short test time.

Test Set Embedding for Deterministic BIST Using a Reconfigurable Interconnection Network

We present a new approach for deterministic built-in self-test (BIST) in which a reconfigurable interconnection network (RIN) is placed between the outputs of a pseudorandom pattern generator and the scan inputs of the circuit under test (CUT). The RIN, which consists only of multiplexer switches, replaces the phase shifter that is typically used in pseudorandom BIST to reduce correlation between the test data bits that are fed into the scan chains. The connections between the linear-feedback shift-register (LFSR) and the scan chains can be dynamically changed (reconfigured) during a test session. In this way, the RIN is used to match the LFSR outputs to the test cubes in a deterministic test set. The control data bits used for reconfiguration ensure that all the deterministic test cubes are embedded in the test patterns applied to the CUT. The proposed approach requires very little hardware overhead, only a modest amount of CPU time, and fewer control bits compared to the storage required for reseeding techniques or for hybrid BIST. Moreover, as a nonintrusive BIST solution, it does not require any circuit redesign and has minimal impact on circuit performance.

An Effective Deterministic BIST Scheme for Shifter/Accumulator Pairs in Datapaths

In this paper an effective Built-In Self-Test (BIST) scheme for the shifter-accumulator pair (accumulation performed either by an adder or an ALU) which appears very often in embedded processor, microprocessor or DSP datapaths is introduced. The BIST scheme provides very high fault coverage (>99%) with respect to the stuck-at fault model for any datapath width with a regular, very small and counter-generated deterministic test set, as it is verified by a comprehensive set of experiments.

A deterministic built-in self-test generator based on cellular automata structures

This paper proposes a new approach for designing a cost-effective, on-chip, deterministic, built-in, self-test generator. Given a set of precomputed test vectors (obtained by an ATPG tool) with a predetermined fault coverage, a simple test vector generator (TVG) is synthesized to apply the given test set in a minimal test time. To achieve this objective, cellular automata (CA) structures have been used in which the rule space is not limited to the linear rules commonly used in CA studies recently. Based on some new notations and new formulations of CA properties, two techniques are developed to synthesize such a TVG which is used to generate an ordered/unordered deterministic test vector set. The resulting TVG is very efficient in terms of hardware size and speed performance, and is very regular and testable. Simulation of various benchmark combinational circuits has given good results when compared to alternative solutions.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Automated Bist for Regular Structures Embedded in Asic Devices

Testing complex very large-scale integrated (VLSI) circuits is increasingly difficult. It is almost impossible to achieve high fault coverages without using design for testability (DFT) approaches. In one of the most promising DFT approaches, the complex VLSI circuit is divided into various structural modules, and an appropriate built-in self-test (BIST) scheme for each module is then implemented. This approach also provides a path to board- and system-level test. This paper presents a general procedure to implement BIST for a specific set of modules, i.e., embedded regular structures such as static random-access memory (SRAM), read-only memory (ROM), and register files. We will show that fault coverages achieved with this procedure are greater than 99 percent, because the deterministic BIST algorithms and output-data compaction techniques adopted are structure-specific. Moreover, fault simulations are not needed because the fault coverages are analytically determined by an algorithmic approach. The general procedure presented here results in an automated BIST implementation. An illustration of such a procedure is presented through the BIST register file example.