High-Speed Logic Level Fault Simulation

Author(s):  
Raimund Ubar ◽  
Sergei Devadze

In the first part of the chapter, an introduction to the problem of logic level fault simulation is given together with the overview of existing fault simulation techniques. The remaining part of the chapter describes a new approach to fault simulation based on exact critical path tracing to conduct fault analysis in logic circuits. A circuit topology driven computational model is presented which allows not only to cope with complex structures of nested reconvergent fan-outs but also to carry out the fault reasoning for many test patterns concurrently. To achieve the speed-up of backtracing, the circuit is simulated on higher than traditional gate level. As components of the circuit network, fan-out free regions of maximum size are considered, and they are represented by structurally synthesized BDDs. The latter allow to reduce the number of internal variables in the computation model, and therefore to process the whole circuit faster than on the flat gate-level. The method is explained first, for the stuck-at fault model, and then generalized for an extended class of functional fault model covering the conditional stuck-at and transition faults. The method can be used for simulating permanent faults in combinational circuits, and transient or intermittent faults both in combinational and sequential circuits with the goal of selecting malicious faults for injecting into fault tolerant systems to evaluate their dependability. Experimental results are included to give an idea how efficiently the method works with different fault classes.

Author(s):  
Peter Marwedel

AbstractUnfortunately, we cannot rely on designed and possibly already manufactured systems to operate as expected. These systems may have become defective during their use, or their function may have been compromised during the fabrication or their design. The purpose of testing is to verify whether or not an existing embedded/cyber-physical system can be operated as expected. In this chapter, we will present fundamental terms and techniques for testing. There will be a brief introduction to the aims of test pattern generation and their application. We will be introducing terms such as fault model, fault coverage, fault simulation, and fault injection. Also, we will be presenting techniques which improve testability, including the generation of pseudo-random patterns, and signature analysis. It would be beneficial to consider testability issues already during design. In case of fault-tolerant systems, resilience must be verified.


2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
Burhan Khurshid ◽  
Roohie Naaz Mir

Generalized parallel counters (GPCs) are used in constructing high speed compressor trees. Prior work has focused on utilizing the fast carry chain and mapping the logic onto Look-Up Tables (LUTs). This mapping is not optimal in the sense that the LUT fabric is not fully utilized. This results in low efficiency GPCs. In this work, we present a heuristic that efficiently maps the GPC logic onto the LUT fabric. We have used our heuristic on various GPCs and have achieved an improvement in efficiency ranging from 33% to 100% in most of the cases. Experimental results using Xilinx 5th-, 6th-, and 7th-generation FPGAs and Stratix IV and V devices from Altera show a considerable reduction in resources utilization and dynamic power dissipation, for almost the same critical path delay. We have also implemented GPC-based FIR filters on 7th-generation Xilinx FPGAs using our proposed heuristic and compared their performance against conventional implementations. Implementations based on our heuristic show improved performance. Comparisons are also made against filters based on integrated DSP blocks and inherent IP cores from Xilinx. The results show that the proposed heuristic provides performance that is comparable to the structures based on these specialized resources.


Author(s):  
Mark Jansen ◽  
Gerald Montague ◽  
Andrew Provenza ◽  
Alan Palazzolo

Closed loop operation of a single, high temperature magnetic radial bearing to 30,000 RPM (2.25 million DN) and 540°C (1,000°F) is discussed. Also, high temperature, fault tolerant operation for the three axis system is examined. A novel, hydrostatic backup bearing system was employed to attain high speed, high temperature, lubrication free support of the entire rotor system. The hydrostatic bearings were made of a high lubricity material and acted as journal-type backup bearings. New, high temperature displacement sensors were successfully employed to monitor shaft position throughout the entire temperature range and are described in this paper. Control of the system was accomplished through a stand alone, high speed computer controller and it was used to run both the fault-tolerant PID and active vibration control algorithms.


VLSI technology become one of the most significant and demandable because of the characteristics like device portability, device size, large amount of features, expenditure, consistency, rapidity and many others. Multipliers and Adders place an important role in various digital systems such as computers, process controllers and signal processors in order to achieve high speed and low power. Two input XOR/XNOR gate and 2:1 multiplexer modules are used to design the Hybrid Full adders. The XOR/XNOR gate is the key punter of power included in the Full adder cell. However this circuit increases the delay, area and critical path delay. Hence, the optimum design of the XOR/XNOR is required to reduce the power consumption of the Full adder Cell. So a 6 New Hybrid Full adder circuits are proposed based on the Novel Full-Swing XOR/XNOR gates and a New Gate Diffusion Input (GDI) design of Full adder with high-swing outputs. The speed, power consumption, power delay product and driving capability are the merits of the each proposed circuits. This circuit simulation was carried used cadence virtuoso EDA tool. The simulation results based on the 90nm CMOS process technology model.


2017 ◽  
Vol 21 (1) ◽  
pp. 3
Author(s):  
Burhan Khurshid

Generalized Parallel Counters (GPCs) are frequently used in constructing high speed compressor trees. Previous work has focused on achieving efficient mapping of GPCs on FPGAs by using a combination of general Look-up table (LUT) fabric and specialized fast carry chains. The  resulting structures are purely combinational and cannot be efficiently pipelined to achieve the potential FPGA performance. In this paper, we take an alternate approach and try to eliminate the fast carry chain from the GPC structure. We present a heuristic that maps GPCs on FPGAS using only general LUT fabric. The resultant GPCs are then easily re-timed by placing registers at the fan-out nodes of each LUT. We have used our heuristic on various GPCs reported in prior work. Our heuristic successfully eliminates the carry chain from the GPC structure with the same LUT count in most of the cases. Experimental results using Xilinx Kintex-7 FPGAs show a considerable reduction in critical path and dynamic power dissipation with same area utilization in most of the cases.


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