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CMOS LowPower Analog Circuit Design
"... This chapter covers device and circuit aspects of lowpower analog CMOS circuit design. The fundamental limits constraining the design of lowpower circuits are first recalled with an emphasis on the implications of supply voltage reduction. Biasing MOS transistors at very low current provides new f ..."
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Cited by 21 (0 self)
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This chapter covers device and circuit aspects of lowpower analog CMOS circuit design. The fundamental limits constraining the design of lowpower circuits are first recalled with an emphasis on the implications of supply voltage reduction. Biasing MOS transistors at very low current provides new features but requires dedicated models valid in all regions of operation including weak, moderate and strong inversion. Lowcurrent biasing also has a strong influence on noise and matching properties. All these issues are discussed, together with the particular aspects related to passive devices and parasitic effects. The design process has to be supported by efficient and accurate circuit simulation. To this end, the EKV compact MOST model for circuit simulation is shortly presented. The use of the basic concepts such as pinchoff voltage, inversion factor and specific current are highlighted thanks to some very simple but fundamental circuits and to an effective use of the model. New design techniques that are appropriate for lowpower and/or lowvoltage circuits are presented with an emphasis on the analog floating point technique, the instantaneous companding principle, and their application to filters.
A Summating, ExponentiallyDecaying CMOS Synapse for Spiking Neural Systems
 Adv. Neural Info. Proc. Syst
, 2004
"... Synapses are a critical element of biologicallyrealistic, spikebased neural computation, serving the role of communication, computation, and modification. Many different circuit implementations of synapse function exist with different computational goals in mind. In this paper we describe a ne ..."
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Cited by 11 (1 self)
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Synapses are a critical element of biologicallyrealistic, spikebased neural computation, serving the role of communication, computation, and modification. Many different circuit implementations of synapse function exist with different computational goals in mind. In this paper we describe a new CMOS synapse design that separately controls quiescent leak current, synaptic gain, and timeconstant of decay. This circuit implements part of a commonlyused kinetic model of synaptic conductance.
An onoff logdomain circuit that recreates adaptive filtering in the retina
 IEEE Trans. Circuits Syst. I, Reg. Papers
, 2005
"... Abstract—We introduce a new approach to synthesizing Class AB logdomain filters that satisfy dynamic differentialmode and commonmode constraints simultaneously. Whereas the dynamic differentialmode constraint imposes the desired filtering behavior, the dynamic commonmode constraint solves the z ..."
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Cited by 8 (6 self)
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Abstract—We introduce a new approach to synthesizing Class AB logdomain filters that satisfy dynamic differentialmode and commonmode constraints simultaneously. Whereas the dynamic differentialmode constraint imposes the desired filtering behavior, the dynamic commonmode constraint solves the zerodcgain problem, a shortcoming of previous approaches. Also, we introduce a novel push–pull circuit that serves as a currentsplitter; it rectifies a differential signal into the ON and OFF paths in our logdomain filter. As an example, we synthesize a firstorder lowpass filter, and, to demonstrate the rejection of dc signals, we implement an adaptive filter by placing this lowpass circuit in a variablegain negativefeedback path. Feedback gain is controlled by signal energy, which is extracted simply by summing complementary ON and OFF signals—dc signals do not contribute to the signal energy nor are they amplified by the feedback. We implement this adaptive filter design in a silicon chip that draws biological inspiration from visual processing in the mammalian retina. It may also be useful in other applications that require dynamic timeconstant adaptation. Index Terms—Adaptive filtering, artificial vision, class AB circuits, neuromorphic engineering.
An RMSDC converter based on the dynamical translinear principle
 in Proc. ESSCIRC
, 1996
"... Translinear or logdomain #lters are theoretically exact realisations of linear di#erential equations. However, the dynamical translinear principle can also be applied to the implementation of nonlinear di#erential equations. In this paper, an RMSDC converter is proposed, comprising a direct imp ..."
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Cited by 7 (3 self)
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Translinear or logdomain #lters are theoretically exact realisations of linear di#erential equations. However, the dynamical translinear principle can also be applied to the implementation of nonlinear di#erential equations. In this paper, an RMSDC converter is proposed, comprising a direct implementation of the corresponding nonlinear di#erential equation by means of the dynamical translinear principle. Correct operation of the circuit was veri#ed through measurements. 1 Introduction The translinear principle #1# plays a key role in conventional implementations of RMStoDC conversion #2#. A wellknown RMSDC converter is shown in Fig. 1. The squarerdivider basically comprises a fourtransistor, i.e. secondorder #3#, translinear loop. As the squarerdivider facilitates onequadrant operation, its input signal is fullwave recti#ed. It calculates the current I 2 in =I out , where I out is the output current of the RMSDC converter and is equal to the mean value of I 2 in ...
Synthesis of LogDomain Filters from FirstOrder Building Blocks
, 2000
"... Logdomain filters are an important class of currentmode circuits having largesignal linearity and increased tuning range over voltagemode filter circuits of similar complexity. In this paper we describe synthesis of a singleended, firstorder filter circuit from static and dynamic translinear ..."
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Cited by 6 (2 self)
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Logdomain filters are an important class of currentmode circuits having largesignal linearity and increased tuning range over voltagemode filter circuits of similar complexity. In this paper we describe synthesis of a singleended, firstorder filter circuit from static and dynamic translinear circuit principles, and show how higherorder filters can be easily constructed from the firstorder building block. We address additional issues related to lowfrequency (audiofrequency) filter design and present results measured from test circuits and a complete 15channel filterbank system fabricated in 2 mm and 1.2 mm BiCMOS processes.
Analysis and Synthesis of Static Translinear Circuits
, 2000
"... This report describes the class of static translinear circuits, which are capable of accurately implementing a wide range of static nonlinear relationships in the current signal domain, such as products, quotients, fixed powerlaw relationships, vector magnitude, and rational functions. After a brie ..."
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Cited by 3 (1 self)
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This report describes the class of static translinear circuits, which are capable of accurately implementing a wide range of static nonlinear relationships in the current signal domain, such as products, quotients, fixed powerlaw relationships, vector magnitude, and rational functions. After a brief historical account of the emergence of the class of translinear circuits, we examine the representation of information in translinear circuits and systems. Then, we describe the translinear principle and its application to the analysis and synthesis of translinearloop circuits, illustrating the processes with several example circuits. We then describe the operation and implementation of a translinearcircuit primitive called the multipleinput translinear element (MITE). From such elements, we build MITE networks, a class of lowvoltage translinear circuits that is equivalent to the class of translinearloop circuits. We describe intuitively the operation of MITE networks. We also describe how to analyze and synthesize such circuits, illustrating these processes with several example circuits.
On the analysis of noise and interference in instantaneously companding signal processors
 University of California, Berkeley, in
, 1998
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Shortening the Analog Design Trajectory By Means of the Dynamic Translinear Principle
"... A promising new approach to shorten the design trajectory of analog integrated circuits without giving up functionality is formed by the class of dynamic translinear circuits. This paper presents a structured design method for this young, yet rapidly developing, circuit paradigm. As a design example ..."
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Cited by 2 (0 self)
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A promising new approach to shorten the design trajectory of analog integrated circuits without giving up functionality is formed by the class of dynamic translinear circuits. This paper presents a structured design method for this young, yet rapidly developing, circuit paradigm. As a design example, a 40¯A 2V dynamic translinear PLL, used as an FM demodulator, is presented. I. Introduction Electronics design can be considered to be the mapping of a set of mathematical functions onto silicon. For discretetime systems, of which the digital systems today are by far the most popular, this comes down to the implementation of a number of difference equations, whereas for continuoustime systems, often denoted by the term analog, differential equations are the starting points. In mixed analogdigital systems, the analog parts, however, often occupy less than ten percent of the complete, i.e., the mixed analogdigital circuitry, whereas their design trajectory is often substantially longe...
A SecondOrder LogDomain Bandpass Filter for Audio Frequency Applications
 International Symposium on Circuits and Systems (ISCAS
, 1998
"... Abstract — Logdomain filters have recently come into the limelight of the VLSI community as an important class of circuits for implementing continuoustime filters in the current domain [4], [3], [2]. Some papers have discussed logdomain circuit analysis [1] and some have addressed circuit synthes ..."
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Cited by 2 (1 self)
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Abstract — Logdomain filters have recently come into the limelight of the VLSI community as an important class of circuits for implementing continuoustime filters in the current domain [4], [3], [2]. Some papers have discussed logdomain circuit analysis [1] and some have addressed circuit synthesis [2], [5], [6], [7]. In this paper we describe synthesis of a secondorder logdomain bandpass filter, address issues related to lowfrequency (audiofrequency) filter design, and show experimental results from a system fabricated in a standard 2 µm BiCMOS technology. I.