A BIST Scheme for Bootstrapped Switches

This paper proposes a built-in self-test (BIST) scheme for detecting catastrophic faults in bootstrapped switches. The clock signal and the gate voltage of the sampling MOS transistor are taken as the observation signals in the proposed BIST scheme. Usually, the gate voltage of the sampling MOS transistor is greater than or equal to the supply voltage when the switch is turn on, and such a voltage is not suitable for observation. To solve this problem, a low power supply voltage is provided for the bootstrapped switch to obtain a suitable observation voltage. The proposed BIST scheme and the circuit under test (CUT) are realized with transistor level. The proposed BIST scheme was simulated by HSPICE. The simulated fault coverage is approximately 87.9% with 66 test circuits.

Design of an Oscillation-Based BIST System for Active Analog Integrated Filters in 0.18 µm CMOS

In this paper, an oscillation-based built-in self-test system for active an analog integrated circuit is presented. This built-in self-test system was used to detect catastrophic and parametric faults, introduced during chip manufacturing. As circuits under test (CUT), second-order Sallen-Key, Akerberg-Mossberg and Tow-Thomas biquad filters were designed. The proposed test hardware detects parametric and catastrophic faults on changeable limits. The influence of both oscillation and test hardware on fault detection limits were investigated and analyzed. The proposed oscillation based self-test system was designed and simulated in 0.18 µm complementary metal-oxide semiconductor (CMOS) technology. Due to the easiness of implementation and configuration for testing of different active analog filters, such self-test systems can be effectively used in modern integrated circuits, made of a large number of devices and circuits, such as the multi-standard transceivers used in the core hardware of software-defined radios. Using the proposed test strategy, the fault tolerance limits for catastrophic faults varied from 96% to 100% for all injected faults in different structures of low pass filters (LPF). The detection range of parametric faults of passive components’ nominal value, depending on the used structure of the filter, did not exceed –0.74% – 0.72% in case of Sallen-Key, –3.31% – 1.00% in case of Akerberg-Mossberg and –2.39% – 1.44% in case of Tow-Thomas LPF.

Fault tolerant area coverage control for multiagent systems

The fault tolerance characteristics of a distributed multi-agent coverage algorithm are examined. A team of sensor-equipped mobile agents is tasked with covering a planar region of interest. A distributed, gradient-based control scheme is utilized for this purpose. The agents are assumed to consist of three subsystems, each one of which may fail. The subsystems under examination are the actuation, sensing and the communication subsystem. Partial and catastrophic faults are examined. Several simulation studies are conducted highlighting the robustness of the distributed nature of the control scheme to these classes of faults, even when several of them happen at the same time.

Optimal Method for Catastrophic Faults Diagnosis in RC Ladder Network

The RC ladder network has been analyzed for various catastrophic fault detection using minimal number of measurements. Generally, electronic circuit testing procedure is very exhaustive and includes higher cost; the presented approach will save fault diagnosis time. It is not possible to analyze the big RC ladder network to give the good fault coverage, so the ladder network has been broken into segments of different sizes. However, if segment size is small, it will cause more area overhead compared to bigger step size in terms of the interconnections and pins on the integrated circuit. A systematic and detailed analysis for one-step, two-step, three-step, and four-step RC ladder networks has been carried out for various faults and optimal step size is proposed. It has been investigated that three measurements are optimal to localize different catastrophic faults in a RC ladder network.

Availability

Protection methods, which were described in the previous chapter, save the converter against non-catastrophic faults. However, this method saves the converter but it also takes the converter out of the service. The subject of this chapter is converters that are not damaged but can not operate normally. In this chapter, availability of electric power converters as a most important but usually forgotten parameter is described. The concept of availability was originally developed for repairable systems that are required to operate continuously. It is explained that a system may be unavailable while none of its parts damaged. In fact, there is an important difference between reliability and availability. A converter may be highly reliable but unavailable and vice versa. One of the most important factors for this undesired state is influence of noise. In this chapter, electromagnetic interference and certain methods for reducing its undesired effects on electric power converters are presented. Electric power converters are usually the source of electromagnetic noise due to high operating voltage and/or current. Various techniques for safe operation of sensitive systems that operate close to these converters are described. In the last part of chapter, alarm management is presented based on availability concept. This method is used to prevent fast shutdown of important systems due to dispensable faults.