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Variable domain transformation for linear PAC analysis of mixed-signal systems
This paper describes a method to perform linear AC analysis on mixed-signal systems which appear strongly nonlinear in the voltage domain but are linear in other variable domains. Common circuits like phase/delay-locked loops and duty-cycle correctors fall into this category, since they are designed to be linear with respect to phases, delays, and duty-cycles of the input and output clocks, respectively. The method uses variable domain translators to change the variables to which the AC perturbation is applied and from which the AC response is measured. By utilizing the efficient periodic AC (PAC) analysis available in commercial RF simulators, the circuitโs linear transfer function in the desired variable domain can be characterized without relying on extensive transient simulations. Furthermore, the variable domain translators enable the circuits to be macromodeled as weakly-nonlinear systems in the chosen domain and then converted to voltage-domain models, instead of being modeled as strongly-nonlinear systems directly
Event-Driven Simulation Methodology for Analog/Mixed-Signal Systems
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ผ๋ฌธ (๋ฐ์ฌ)-- ์์ธ๋ํ๊ต ๋ํ์ : ์ ๊ธฐยท์ปดํจํฐ๊ณตํ๋ถ, 2015. 8. ๊น์ฌํ.Recent system-on-chip's (SoCs) are composed of tightly coupled analog and digital components. The resulting mixed-signal systems call for efficient system-level behavioral simulators for fast and systematic verifications. As the system-level verifications rely heavily on digital verification tools, it is desirable to build the mixed-signal simulator based on a digital simulator. However, the existing solutions in digital simulators suffer from a trade-off between simulation speed and accuracy. This work breaks down the trade-off and realizes a fast and accurate analog/mixed-signal behavior simulation in a digital simulator SystemVerilog.
The main difference of the proposed methodology from existing ones is its way of representing continuous-time signals. Specifically, a clock signal expresses accurate timing information by carrying an additional real-value time offset, and an analog signal represents its continuous-time waveform in a functional form by employing a set of coefficients. With these signal representations, the proposed method accurately simulates mixed-signal behaviors independently of a simulator's time-step and achieves a purely event-driven simulation without involving any numerical iteration.
The speed and accuracy of the proposed methodology are examined for various types of analog/mixed-signal systems. First, timing-sensitive circuits (a phase-locked loops and a clock and data recovery loop) and linear analog circuits (a channel and linear equalizers) are simulated in a high-speed I/O interface example. Second, a switched-linear-behavior simulation is demonstrated through switching power supplies, such as a boost converter and a switched-capacitor converter. Additionally, the proposed method is applied to weakly nonlinear behaviors modeled with a Volterra series for an RF power amplifier and a high-speed I/O linear equalizer. Furthermore, the nonlinear behavior simulation is extended to three different types of injection-locked oscillators exhibiting time-varying nonlinear behaviors. The experimental results show that the proposed simulation methodology achieved tens to hundreds of speed-ups while maintaining the same accuracy as commercial analog simulators.ABSTRACT I
CONTENTS III
LIST OF FIGURES V
LIST OF TABLES XII
CHAPTER 1 INTRODUCTION 1
1.1 BACKGROUND 1
1.2 MAIN CONTRIBUTION 6
1.3 THESIS ORGANIZATION 8
CHAPTER 2 EVENT-DRIVEN SIMULATION OF ANALOG/MIXED-SIGNAL BEHAVIORS 9
2.1 PROPOSED CLOCK AND ANALOG SIGNAL REPRESENTATIONS 10
2.2 SIGNAL TYPE DEFINITIONS IN SYSTEMVERILOG 14
2.3 EVENT-DRIVEN SIMULATION METHODOLOGY 16
CHAPTER 3 HIGH-SPEED I/O INTERFACE SIMULATION 21
3.1 CHARGE-PUMP PHASE-LOCKED LOOP 23
3.2 BANGBANG CLOCK AND DATA RECOVERY 37
3.3 CHANNEL AND EQUALIZERS 45
3.4 HIGH-SPEED I/O SYSTEM SIMULATION 52
CHAPTER 4 SWITCHING POWER SUPPLY SIMULATION 55
4.1 BOOST CONVERTER 57
4.2 TIME-INTERLEAVED SWITCHED-CAPACITOR CONVERTER 66
CHAPTER 5 VOLTERRA SERIES MODEL SIMULATION 72
5.1 VOLTERRA SERIES MODEL 74
5.2 CLASS-A POWER AMPLIFIER 79
5.3 CONTINUOUS-TIME EQUALIZER 84
CHAPTER 6 INJECTION-LOCKED OSCILLATOR SIMULATION 89
6.1 PPV-BASED ILO MODEL 91
6.2 LC OSCILLATOR 99
6.3 RING OSCILLATOR 104
6.4 BURST-MODE CLOCK AND DATA RECOVERY 109
CONCLUSION 116
BIBLIOGRAPHY 118
์ด ๋ก 126Docto