A Hierarchical Performance Equation Library for Basic Op-Amp Design

Abel, Inga; Neuner, Maximilian; Graeb, Helmut

doi:10.1109/tcad.2021.3101691

Cited by 12 publications

(18 citation statements)

References 38 publications

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“…The largest deviation occurs for the unity-gain bandwidth. Its value is overestimated in the sizing process as it depends linearly on the input conductance of the irst stage in the analytical equations [7,29].…”

Section: Sizing and Evaluation Resultsmentioning

confidence: 99%

“…in [29], a behavioral model based on analytical equations for each functional block described in Sec. 2 was developed leading to a hierarchical performance equation library [7] allowing an topology independent equation set-up. This makes this method unique compared to other state-of-the-art equation-based sizing methods [5,6,11,14,15,18,27,30,32,34,48,51,52].…”

Section: Topology Sizing and Evaluationmentioning

confidence: 99%

“…As the structure of the op-amp and its ampliication stages is known through the composition graph (Fig. 3a), the equations for an op-amps are automatically instantiated as described in [7].…”

Section: Topology Sizing and Evaluationmentioning

confidence: 99%

“…For given speciications, the netlists are evaluated using an analytical equation-based sizing method similar to [6]. A library was developed storing analytical behavior models for every functional block in an op-amp [7]. Useless conigurations are avoided in an early phase of the structural synthesis process.…”

Section: Introductionmentioning

confidence: 99%

“…Numerical Feats [37] > 10 000 Graph algorithm on basic building blocks library 8 h Numerical Zhao [56] 4000 approaches based on equation-based methods to evaluate circuit topologies, e.g., [24,35], use a topology selection method to decide for a topology. This is diferent in this method as the topology independent sizing process presented in detail in [7] allows the synthesis and evaluation of thousands of diferent topologies, as the set-up of the equation-based description is automated. The hierarchical functional block composition (FUBOCO) graph of the method introduced in this paper omits many redundant and design-irrelevant topologies.…”

Section: Introductionmentioning

confidence: 99%

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FUBOCO: Structure Synthesis of Basic Op-Amps by FUnctional BlOck COmposition

Abel

Graeb

2022

ACM Trans. Des. Autom. Electron. Syst.

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This paper presents a method to automatically synthesize the structure and initial sizing of an operational amplifier. It is positioned between approaches with fixed design plans and a small search space of structures and approaches with generic structural production rules and a large search space with technically impractical structures. The presented approach develops a hierarchical composition graph based on functional blocks that spans a search space of thousands of technically meaningful structure variants for single-output, fully-differential and complementary operational amplifiers. The search algorithm is a combined heuristic and enumerative process. The evaluation is based on circuit sizing with a library of behavioral equations of functional blocks. Formalizing the knowledge of functional blocks in op-amps for structural synthesis and sizing inherently reduces the search space and lessens the number of created topologies not fulfilling the specifications. Experimental results for the three op-amp classes are presented. An outlook how this method can be extended to multi-stage op-amps is given.

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Section: Sizing and Evaluation Resultsmentioning

confidence: 99%

Section: Topology Sizing and Evaluationmentioning

confidence: 99%

Section: Topology Sizing and Evaluationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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FUBOCO: Structure Synthesis of Basic Op-Amps by FUnctional BlOck COmposition

Abel

Graeb

2022

ACM Trans. Des. Autom. Electron. Syst.

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Automatic generation of macromodels and design equations for application to Op Amp design

Shi

2023

Circuit Theory & Apps

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SummaryOperational amplifier (Op Amp) is a special class of analog integrated circuits. Multiple‐stage Op Amp design is of particular interest recently. However, analysis of this class of circuits has to be done manually and requires advanced skills. Automatic analysis of this class of circuits is studied in this paper, which takes a novel approach by circuit recognition and symbolic generation. Circuit recognition is deterministic, implemented by deterministic circuit partitioning and functional block extraction methods. Symbolic analysis of extracted circuit blocks can subsequently be performed with greatly reduced complexity while generated models and equations bear more useful information for circuit design. Symbolic results so generated can be applied in design space exploration, including tasks like finding the limitation in circuit topology, conducting initial sizing, and determining performance tradeoffs. This paper proposes the key algorithms for realizing the recognition of a few well‐known functional blocks frequently used in CMOS Op Amp circuits and further explores the possibility of using the recognized circuit cells in combination with the gm/ID method for circuit sizing. Preliminary tests show that this approach is a potential candidate for locating the performance boundaries of multiple‐stage Op Amps.

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