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A TransientEnhanced LowQuiescent Current LowDropout Regulator With Buffer Impedance Attenuation
"... Abstract—This paper presents a lowdropout regulator (LDO) for portable applications with an impedanceattenuated buffer for driving the pass device. Dynamicallybiased shunt feedback is proposed in the buffer to lower its output resistance such that the pole at the gate of the pass device is pushed ..."
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Abstract—This paper presents a lowdropout regulator (LDO) for portable applications with an impedanceattenuated buffer for driving the pass device. Dynamicallybiased shunt feedback is proposed in the buffer to lower its output resistance such that the pole at the gate of the pass device is pushed to high frequencies without dissipating large quiescent current. By employing the currentbuffer compensation, only a single pole is realized within the regulation loop unitygain bandwidth and over 65 phase margin is achieved under the full range of the load current in the LDO. The LDO thus achieves stability without using any lowfrequency zero. The maximum outputvoltage variation can be minimized during load transients even if a small output capacitor is used. The LDO with the proposed impedanceattenuated buffer has been implemented in a 0.35 m twinwell CMOS process. The proposed LDO dissipates 20 A quiescent current at noload condition and is able to deliver up to 200mA load current. With a1F output capacitor, the maximum transient outputvoltage variation is within 3 % of the output voltage with load step changes of 200 mA/100 ns. Index Terms—Linear regulator, load transient response, lowdropout regulator (LDO), pass device, power management integrated circuits, voltage buffer. I.
Automated design of operational transconductance amplifiers using reversed geometric programming
 In Proceedings of the 41th IEEE/ACM Design Automation Conference
, 2004
"... We present a method for designing operational amplifiers using reversed geometric programming, which is an extension of geometric programming that allows both convex and nonconvex constraints. Adding a limited set of nonconvex constraints can improve the accuracy of convex equationbased optimizati ..."
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We present a method for designing operational amplifiers using reversed geometric programming, which is an extension of geometric programming that allows both convex and nonconvex constraints. Adding a limited set of nonconvex constraints can improve the accuracy of convex equationbased optimization, without compromising global optimality. These constraints allow increased accuracy for critical modeling equations, such as the relationship between gm and IDS. To demonstrate the design methodology, a foldedcascode amplifier is designed in a 0.18 µm technology for varying speed requirements and is compared with simulations and designs obtained from geometric programming. Categories and Subject Descriptors:
Automatic synthesis of operational amplifiers based on analytic circuit models
 Proceedings of IEEE International Conference on ComputerAided Design
, 1987
"... An automatic synthesis tool for CMOS op amps (OPASYN) has been developed. The program starts from one of a number of op amp circuits and proceeds to optimize various device sizes and bias currents to meet a given set of design specifications. Because it uses analytic circuit models in its inner opti ..."
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Cited by 4 (0 self)
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An automatic synthesis tool for CMOS op amps (OPASYN) has been developed. The program starts from one of a number of op amp circuits and proceeds to optimize various device sizes and bias currents to meet a given set of design specifications. Because it uses analytic circuit models in its inner optimization loop, it can search efficiently through a large part of the possible solution space. The program has a SPICE interface that automatically performs circuit simulations for the candidate solutions to verify the results of the synthesis and optimization procedure. The simulation results are also used to finetune the analytic circuit descriptions in the database. OPASYN has been implemented in Franz Lisp and demonstrated for three different basic circuits with a conventional 3 µm process and a more advanced 1.5 µm process. Experiments have shown that OPASYN quickly produces practical designs which will meet reasonable design objectives. 1.
jpvQeecs.berkeley.edu
"... We present a method for designing operational amplifiers using reversed geometric programming, which is an extension of geometric programming that allows both convex and nonconvex constraints. Adding a limited set of nonconvex constraints can improve the accuracy of convex equationbased optimizati ..."
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We present a method for designing operational amplifiers using reversed geometric programming, which is an extension of geometric programming that allows both convex and nonconvex constraints. Adding a limited set of nonconvex constraints can improve the accuracy of convex equationbased optimization, without compromising global optimality. These constraints allow increased accuracy for critical modeling equations, such as the relationship between gm and Ips. To demonstrate the design methodology, a foldedcascode amplifier is designed in a 0.18'pm technology for varying speed requirements and is compared with simnlations and designs obtained from geometric programming. Categories and Subject Descriptors:
UNIVERSITÉ DE GRENOBLE THÈSE Pour obtenir le grade de
, 2013
"... Thèse dirigée par Laurent FESQUET et ..."
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10.1 Automated Design of Operational Transconductance Amplifiers using Reversed Geometric Programming
"... We present a method for designing operational amplifiers using reversed geometric programming, which is an extension of geometric programming that allows both convex and nonconvex constraints. Adding a limited set of nonconvex constraints can improve the accuracy of convex equationbased optimizati ..."
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We present a method for designing operational amplifiers using reversed geometric programming, which is an extension of geometric programming that allows both convex and nonconvex constraints. Adding a limited set of nonconvex constraints can improve the accuracy of convex equationbased optimization, without compromising global optimality. These constraints allow increased accuracy for critical modeling equations, such as the relationship between gm and IDS. To demonstrate the design methodology, a foldedcascode amplifier is designed in a 0.18 µm technology for varying speed requirements and is compared with simulations and designs obtained from geometric programming. Categories and Subject Descriptors:
Accurate Transient Response Model for Automatic Synthesis of HighSpeed Operational Amplifiers
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Representative of Graduate Studies
, 2006
"... Sigma delta modulators (ΣΔMs) form part of the core of today’s mixedsignal designs. They are cornerstone components of oversampled data converters. Such data converters take advantage of digital signal processing techniques and VLSI technology to provide high performance with low sensitivity to an ..."
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Sigma delta modulators (ΣΔMs) form part of the core of today’s mixedsignal designs. They are cornerstone components of oversampled data converters. Such data converters take advantage of digital signal processing techniques and VLSI technology to provide high performance with low sensitivity to analog component imperfections and noisy conditions. The ongoing research on these devices shows the potential of ΣΔ data converters as a promising candidate for highspeed, highresolution, and lowpower mixedsignal interfaces. As for any electronic system, efficient modeling and simulation tools are essential in the design cycle of oversampled converters, particularly for their embedded ΣΔMs. Although transistorlevel simulation is the most accurate approach known for these components, this method becomes impractical for complex systems due to the long computational time required. This situation has led circuit designers to consider alternate modeling techniques. Among these, the simulation of ΣΔMs using behavioral models has become the focus of attention for a large portion of the design community. This thesis presents an accurate behav