4 research outputs found
Automatic Tuning of Digital Circuits.
Variation in transistors is increasing as process technology transistor dimensions shrink. Compounded with lowering supply voltage, this increased variation presents new challenges for the circuit designer. However, this variation also brings many new opportunities for the circuit designer to leverage as well.
We present a time-to-digital converter embedded inside a 64-bit processor core, for direct monitoring of on-chip critical paths. This path monitoring allows the processor to monitor process variation and run-time variations. By adjusting to both static and dynamic operating conditions the impact of variations can be reduced. The time-to-digital converter achieves high-resolution measurement in the picosecond range, due to self-calibration via a self-feedback mode. This system is implemented in 45nm silicon and measured silicon results are shown. We also examine techniques for enhanced variation-tolerance in subthreshold digital circuits, applying these to a high fan-in, self-timed transition detection circuit that, due to its self-timing, is able to fully compensate for the large variation in subthreshold.
In addition to mitigating variations we also leverage them for random number generation. We demonstrate that the randomness inherent in the oxide breakdown process can be extracted and applied for the specific applications of on-chip ID generation and on-chip true random number generation. By using dynamic automated self-calibrating algorithms that tune and control the on-chip circuitry, we are able to achieve extremely high-quality results. The two systems are implemented in 65 nm silicon. Measured results for the on-chip ID system, called OxID, show a high-degree of randomness and read-stability in the generated IDs, both primary prerequisites of a high-quality on-chip ID system. Measured results for the true random number generator, called OxiGen, show an exceptionally high degree of randomness, passing all fifteen NIST 800-22 tests for randomness with statistical significance and without the aid of a post-processor.Ph.D.Electrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/86390/1/rachliu_1.pd
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λ λλ μ΄ λ²νΌμ μν λ©΄μ μ¦κ°λ₯Ό μνν μ μλ ν©μ± κΈ°λ²μ μ μνμλ€.1 INTRODUCTION 1
1.1 Flexible Flip-Flop Timing Model 1
1.2 Hardware Performance Monitoring Methodology 4
1.3 Asynchronous Pipeline Controller 10
1.4 Contributions of this Dissertation 15
2 ANALYSIS AND OPTIMIZATION CONSIDERING FLEXIBLE FLIP-FLOP TIMING MODEL 17
2.1 Preliminaries 17
2.1.1 Terminologies 17
2.1.2 Timing Analysis 20
2.1.3 Clock-to-Q Delay Surface Modeling 21
2.2 Clock-to-Q Delay Interval Analysis 22
2.2.1 Derivation 23
2.2.2 Additional Constraints 26
2.2.3 Analysis: Finding Minimum Clock Period 28
2.2.4 Optimization: Clock Skew Scheduling 30
2.2.5 Scalable Speedup Technique 33
2.3 Experimental Results 37
2.3.1 Application to Minimum Clock Period Finding 37
2.3.2 Application to Clock Skew Scheduling 39
2.3.3 Efficacy of Scalable Speedup Technique 43
2.4 Summary 44
3 HARDWARE PERFORMANCE MONITORING METHODOLOGY AT NTC AND ADVANCED TECHNOLOGY NODE 45
3.1 Overall Flow of Proposed HPM Methodology 45
3.2 Prerequisites to HPM Methodology 47
3.2.1 BEOL Process Variation Modeling 47
3.2.2 Surrogate Model Preparation 49
3.3 HPM Methodology: Design Phase 52
3.3.1 HPM2PV Model Construction 52
3.3.2 Optimization of Monitoring Circuits Configuration 54
3.3.3 PV2CPT Model Construction 58
3.4 HPM Methodology: Post-Silicon Phase 60
3.4.1 Transfer Learning in Silicon Characterization Step 60
3.4.2 Procedures in Volume Production Phase 61
3.5 Experimental Results 62
3.5.1 Experimental Setup 62
3.5.2 Exploration of Monitoring Circuits Configuration 64
3.5.3 Effectiveness of Monitoring Circuits Optimization 66
3.5.4 Considering BEOL PVs and Uncertainty Learning 68
3.5.5 Comparison among Different Prediction Flows 69
3.5.6 Effectiveness of Prediction Model Calibration 71
3.6 Summary 73
4 LIGHTENING ASYNCHRONOUS PIPELINE CONTROLLER 75
4.1 Preliminaries and State-of-the-Art Work 75
4.1.1 Bundled-data vs. Dual-rail Asynchronous Circuits 75
4.1.2 Two-phase vs. Four-phase Bundled-data Protocol 76
4.1.3 Conventional State-of-the-Art Pipeline Controller Template 77
4.2 Delay Path Sharing for Lightening Pipeline Controller Template 78
4.2.1 Synthesizing Sharable Delay Paths 78
4.2.2 Validating Logical Correctness for Sharable Delay Paths 80
4.2.3 Reformulating Timing Constraints of Controller Template 81
4.2.4 Minimally Allocating Delay Buffers 87
4.3 In-depth Pipeline Controller Template Synthesis with Delay Path Reusing 88
4.3.1 Synthesizing Delay Path Units 88
4.3.2 Validating Logical Correctness of Delay Path Units 89
4.3.3 Updating Timing Constraints for Delay Path Units 91
4.3.4 In-depth Synthesis Flow Utilizing Delay Path Units 95
4.4 Experimental Results 99
4.4.1 Environment Setup 99
4.4.2 Piecewise Linear Modeling of Delay Path Unit Area 99
4.4.3 Comparison of Power, Performance, and Area 102
4.5 Summary 107
5 CONCLUSION 109
5.1 Chapter 2 109
5.2 Chapter 3 110
5.3 Chapter 4 110
Abstract (In Korean) 127Docto