scholarly journals A New Approach to Biasing Design of Analog Circuits

10.5772/14244 ◽  
2011 ◽  
Author(s):  
Reza Hashemian
Keyword(s):  
1991 ◽  
Vol 01 (02) ◽  
pp. 149-176 ◽  
Author(s):  
KRZYSZTOF WAWRYN

This article deals with a new approach to an intelligent analog circuit design. The iterative closed loop design methodology adopts an expert system approach to provide topological synthesis, the SPICE circuit simulator to evaluate the circuit performance and a new approach of the diagnostic expert system to provide advice on how to improve the design. Unlike previous design methods, this approach introduces formal circuit representation for both numerical and heuristic knowledge of the design system. The predicate logic circuit representation is proposed to introduce a new concept of a formal analog circuit description language. The language syntax and semantics provide precise symbolic description of analog circuits functionality at different levels of hierarchy and connectivities together with transistor sizes of CMOS circuits at the transistor level. Different levels of hierarchy with circuit structures and performance parameters are presented in detail. It is shown how sentence conversion rules of language grammar can be used to derive transistor level circuits from input performance specifications through all intermediate levels of hierarchy. The implementation of the methodology and associated experimental results for CMOS operational amplifier designs are presented.


2012 ◽  
Vol 21 (08) ◽  
pp. 1240022 ◽  
Author(s):  
MICHAEL PEHL ◽  
HELMUT GRAEB

The design of circuits which are robust against variations in operating and process conditions is crucial in today's IC industry. In the analog design flow this problem can be tackled during the sizing of a new circuit. However, hardly any methods are available which support the designer to compute such a robust design if discrete parameters should be considered in this design step. Discrete parameters arise predominantly if a layout-friendly sizing should be computed in the sense that, e.g., a manufacturing grid for the transistor lengths and widths is considered or that transistor multipliers are used to allow the layout of a transistor as multifinger or common centroid structure without applying rounding operations to the carefully computed sizing. This paper presents a new Branch-and-Bound based approach which allows the automatic computation of a robust design using classical and realistic worst case analysis. The results of the sizing of three circuits show that the new approach is highly efficient. The robustness of the results computed by the new approach is validated by Monte Carlo analyses.


1999 ◽  
Vol 173 ◽  
pp. 185-188
Author(s):  
Gy. Szabó ◽  
K. Sárneczky ◽  
L.L. Kiss

AbstractA widely used tool in studying quasi-monoperiodic processes is the O–C diagram. This paper deals with the application of this diagram in minor planet studies. The main difference between our approach and the classical O–C diagram is that we transform the epoch (=time) dependence into the geocentric longitude domain. We outline a rotation modelling using this modified O–C and illustrate the abilities with detailed error analysis. The primary assumption, that the monotonity and the shape of this diagram is (almost) independent of the geometry of the asteroids is discussed and tested. The monotonity enables an unambiguous distinction between the prograde and retrograde rotation, thus the four-fold (or in some cases the two-fold) ambiguities can be avoided. This turned out to be the main advantage of the O–C examination. As an extension to the theoretical work, we present some preliminary results on 1727 Mette based on new CCD observations.


Author(s):  
V. Mizuhira ◽  
Y. Futaesaku

Previously we reported that tannic acid is a very effective fixative for proteins including polypeptides. Especially, in the cross section of microtubules, thirteen submits in A-tubule and eleven in B-tubule could be observed very clearly. An elastic fiber could be demonstrated very clearly, as an electron opaque, homogeneous fiber. However, tannic acid did not penetrate into the deep portion of the tissue-block. So we tried Catechin. This shows almost the same chemical natures as that of proteins, as tannic acid. Moreover, we thought that catechin should have two active-reaction sites, one is phenol,and the other is catechole. Catechole site should react with osmium, to make Os- black. Phenol-site should react with peroxidase existing perhydroxide.


Author(s):  
K. Chien ◽  
R. Van de Velde ◽  
I.P. Shintaku ◽  
A.F. Sassoon

Immunoelectron microscopy of neoplastic lymphoma cells is valuable for precise localization of surface antigens and identification of cell types. We have developed a new approach in which the immunohistochemical staining can be evaluated prior to embedding for EM and desired area subsequently selected for ultrathin sectioning.A freshly prepared lymphoma cell suspension is spun onto polylysine hydrobromide- coated glass slides by cytocentrifugation and immediately fixed without air drying in polylysine paraformaldehyde (PLP) fixative. After rinsing in PBS, slides are stained by a 3-step immunoperoxidase method. Cell monolayer is then fixed in buffered 3% glutaraldehyde prior to DAB reaction. After the DAB reaction step, wet monolayers can be examined under LM for presence of brown reaction product and selected monolayers then processed by routine methods for EM and embedded with the Chien Re-embedding Mold. After the polymerization, the epoxy blocks are easily separated from the glass slides by heatingon a 100°C hot plate for 20 seconds.


Author(s):  
W. A. Chiou ◽  
N. Kohyama ◽  
B. Little ◽  
P. Wagner ◽  
M. Meshii

The corrosion of copper and copper alloys in a marine environment is of great concern because of their widespread use in heat exchangers and steam condensers in which natural seawater is the coolant. It has become increasingly evident that microorganisms play an important role in the corrosion of a number of metals and alloys under a variety of environments. For the past 15 years the use of SEM has proven to be useful in studying biofilms and spatial relationships between bacteria and localized corrosion of metals. Little information, however, has been obtained using TEM capitalizing on its higher spacial resolution and the transmission observation of interfaces. The research presented herein is the first step of this new approach in studying the corrosion with biological influence in pure copper.Commercially produced copper (Cu, 99%) foils of approximately 120 μm thick exposed to a copper-tolerant marine bacterium, Oceanospirillum, and an abiotic culture medium were subsampled (1 cm × 1 cm) for this study along with unexposed control samples.


Author(s):  
Arthur V. Jones

With the introduction of field-emission sources and “immersion-type” objective lenses, the resolution obtainable with modern scanning electron microscopes is approaching that obtainable in STEM and TEM-but only with specific types of specimens. Bulk specimens still suffer from the restrictions imposed by internal scattering and the need to be conducting. Advances in coating techniques have largely overcome these problems but for a sizeable body of specimens, the restrictions imposed by coating are unacceptable.For such specimens, low voltage operation, with its low beam penetration and freedom from charging artifacts, is the method of choice.Unfortunately the technical dificulties in producing an electron beam sufficiently small and of sufficient intensity are considerably greater at low beam energies — so much so that a radical reevaluation of convential design concepts is needed.The probe diameter is usually given by


1968 ◽  
Vol 32 (3) ◽  
pp. 279-282
Author(s):  
JI Mock ◽  
JW Grenfell ◽  
WA Richter
Keyword(s):  

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