조정 기술을 활용하는 링 발진기 기반의 클럭 생성 회로의 설계

학위논문(박사) -- 서울대학교대학원 : 공과대학 전기·정보공학부, 2023. 2. 정덕균.As demands for wide-band operations increase and sub-rate architectures for reducing power consumption in wireline communications become promising, a ring oscillator (RO) that has a wide frequency range and a capability to generate multi-phase becomes a prospective replacement for LC counterparts. However, the RO, whose frequency is determined by the propagation delay of active devices is vulnerable to supply noise and has the fatal disadvantage of inferior phase noise compared to the LC counterparts. In this dissertation, solutions for the two major drawbacks of RO-based clock generators are addressed, and each solution is verified by a prototype chip. First of all, a RO-based all-digital phase-locked loop (AD-PLL) with a self-biased supply-noise-compensation (SNC) technique for a DDR5 registering clock driver (RCD) application is presented. Considering prerequisites for the DDR5 RCD application, an open-loop SNC-RO that achieves a low frequency-pushing factor with a large static voltage margin is proposed. Since the SNC technique operates independently of the PLL loop bandwidth without using feedback, the SNC-PLL is free from the stability problem associated with bandwidth overlapping, and the SNC performance can be maintained regardless of operating configurations. Furthermore, the SNC technique does not require a start-up circuit and does not deteriorate a stabilization time. Quantitative analyses on static and dynamic characteristics of the proposed SNC technique and relevant design-oriented considerations are addressed. The prototype chip is fabricated in a 28-nm CMOS technology, and the measurement results demonstrate that the AD-PLL satisfies the prerequisites for the SNC technique in the RCD application. The SNC-PLL achieves the best power-supply-noise-attenuation (PSNA) performance of 40 dB and maintains the PSNA performance over 20 dB up to 10 MHz. In the case of random supply noise, the integrated RMS jitter performance is improved by about 65% on average. The AD-PLL consumes 12.1 mW at 3.0 GHz operation and achieves an integrated RMS jitter of 271 fs without any injected supply noise. Secondly, an injection-locked clock multiplier (ILCM) with a new background calibration technique, so-called multi-phase-based calibration (MPC), that utilizes an intrinsic multi-phase generation capability of the RO is presented. To achieve a high suppression bandwidth of RO-induced noises, an injection-locking technique is employed. However, it requires an indispensable two-point (a frequency error (FE) and an injection path offset (PO)) calibration to ensure its normal operation and secure its remarkable jitter performance. With the FE calibrator that operates at every injection rate, the high bandwidth of the FE calibration with full injection effects is attained simultaneously, which contributes to achieving a much lower jitter. The PO calibrator makes the MPC-ILCM converge to a minimum reference spur position, where the residue of the FE in the steady state is minimized. For a low-power implementation, all calibration loops operate at the reference clock rate using sub-sampling bang-bang phase detectors. Time-domain analysis of the behavior of the injection locking and detailed MPC operations with associated requirement conditions are addressed. Fabricated in a 28-nm CMOS, the proposed MPC verifies a low-jitter and low-reference-spur RO-based ILCM. It achieves an integrated RMS jitter of 143.6 fs and a reference spur of -77.9 dBc with a FoM of -247.1 dB at 4.8 GHz operation. The MPC sustains a successful injection-locked condition, hence both the integrated RMS jitter and reference spur performances are maintained with supply voltage variations.광대역 작동에 대한 수요가 증가하고 전력 소비를 줄이기 위한 하위 속도 구조가 유망해짐에 따라, 넓은 주파수 범위와 다상 생성 기능을 갖춘 링 발진기가 LC 공진기의 대체품으로 유망하다. 그러나 능동 소자의 전파 지연에 의해 주파수가 결정되는 링 발진기는 전원 잡음에 취약하고 LC 공진기에 비해 위상 잡음 성능이 취약하다는 단점을 갖는다. 본 논문에서는 링 발진기 기반 클럭 발생기의 두 가지 주요한 단점을 극복하기 위한 해결법을 제안하고, 각 해결법은 칩 설계를 통해 검증된다. 먼저, 자체적으로 전원 잡음을 보상하는 기술이 적용된 링 발진기 기반의 DDR5 RCD용 위상 고정 루프를 제시한다. DDR5 RCD에 적용 가능한 전제 조건을 고려하여, 큰 정적 전압 마진으로 낮은 주파수 민감성을 달성하는 개방 루프형 전원 잡음을 보상하는 링 발진기를 제안한다. 이 기술은 피드백을 사용하지 않고 위상 고정 루프의 대역폭과 독립적으로 동작하기 때문에, 대역폭 중첩과 관련된 안정성 문제로부터 자유로우면서 동작 환경에 관계없이 전원 잡음 보상 성능을 유지할 수 있다. 또한 시동 회로를 필요로 하지 않고, 안정화 시간을 저하시키지 않는다. 제안된 전원 잡음 보상 기술의 정적 및 동적 특성에 대한 정량적 분석과 설계 지향적 고려 사항에 대해 다룬다. 28 나노미터 CMOS 공정으로 제작된 프로토타입 칩의 측정 결과를 통해 RCD 제품의 전원 잡음 보상 기술과 관련된 전제조건을 만족하는 것을 보인다. 본 위상 고정 루프는 40 dB의 최고 PSNA 성능을 달성하고, 10 MHz까지 20 dB 이상의 PSNA 성능을 유지한다. 임의 공급 잡음의 경우, RMS 지터 성능이 평균적으로 약 65 % 개선된다. 본 위상 고정 루프는 3.0 GHz 동작에서 12.1 mW의 전력을 소비하고, 공금 전원 잡음이 없는 환경에서 271 fs의 RMS 지터를 달성한다. 두번째로는 링 발진기의 고유한 다중 위상 생성 기능을 활용하는 새로운 백그라운드 보정 기술이 포함된 주입 고정 클럭 합성기를 제시한다. 링 발진기의 잡음을 줄이기 위한 높은 억제 대역폭을 달성하기 위해 주입 고정 기술이 사용된다. 그러나 정상 동작을 보장하고 뛰어난 지터 성능을 확보하기 위해 필수적인 2점 교정을 필요로 한다. 주입 펄스 속도로 동작하는 주파수 오류 보정기는 높은 주파수 오류 보정 대역폭과 완전한 주입 효과가 동시에 달성되어, 링 발진기의 플리커 잡음을 더욱 억제시켜 훨씬 더 낮은 지터를 달성하는데 기여한다. 경로 오프셋 보정기는 다상 기반 조정 기술의 주입 고정 클럭 합성기가 보정 이후 남아있는 주파수 오류가 최소화가 되어 최소 기준 스퍼의 위치로 수렴되도록 한다. 정상 상태에서 주입 고정 동작에 대한 시간 영역 분석과 다중 위상 보정기의 자세한 동작에 대해 다룬다. 28 나노미터 CMOS 공정으로 제작된 다중 위상 보정기는 4.8 GHz 동작에서 -247.1 dB의 FoM과 143.6 fs의 낮은 지터 및 -77.9 dBc의 낮은 기준 스퍼를 갖는 링 발진기 기반의 주입 고정 클럭 합성기를 입증한다. 다중 위상 보정기는 성공적인 주입 잠금 상태를 유지하여, RMS 지터와 기준 스퍼 성능이 공급 전압 변동에도 유지된다.1 Introduction 1 1.1 Motivation 1 1.2 Dissertation Objectives 4 2 Background on RO-Based Clock Generator 5 2.1 All-Digital Phase-Locked Loop (AD-PLL) 6 2.1.1 AD-PLL Fundamentals 6 2.1.2 Phase Noise Analysis of AD-PLL 11 2.1.3 Effect of Supply Noise in PLL System 16 2.2 Injection-Locked Clock Multiplier (ILCM) 18 2.2.1 Basics of Injection-Locked Oscillator (ILO) 18 2.2.2 Phase Domain Response (PDR) Analysis 22 2.2.3 Phase Noise of ILCM 26 3 Self-Biased Supply-Noise-Compensating RO 31 3.1 Overview 31 3.2 Design Motivation 33 3.2.1 Design Consideration of SNC for RCD application 33 3.2.2 Prior Works Regarding SNC Techniques 34 3.3 Proposed Self-Biased SNC-RO 38 3.3.1 Principle of Nataga Current Source 38 3.3.2 Circuit Description of Self-Biased SNC-RO 39 3.3.3 Design-Oriented Analysis 42 3.3.4 Evaluation on Suitability in RCD application 48 3.4 Circuit Implementation 54 3.4.1 Overall Architecture 54 3.4.2 Circuit Description of Building Blocks: TDC-PFD 55 3.4.3 Circuit Description of Building Blocks: A-FTL 59 3.5 Measurement Results 61 3.5.1 Open-Loop SNC Performance 62 3.5.2 Closed-Loop SNC Performance 64 3.5.3 Fast Stabilization Performance 68 3.5.4 Performance Comparison 69 3.6 Summary 71 4 ILCM with Multi-Phase-Based Calibration 72 4.1 Overview 72 4.2 Design Motivation 74 4.2.1 Needs for Two-Point Calibration in Injection-Locking 74 4.2.2 Prior Works Regarding Two-Point Calibration 79 4.3 Proposed Multi-Phase-Based Calibration (MPC) 81 4.3.1 Logical Process of Creating MPC 82 4.3.2 Time-Domain Analysis of MPC 84 4.3.3 Conceptual Block Diagram of MPC 88 4.3.4 MPC Operation (1, 2): FE Calibration and DLL 92 4.3.5 MPC Operation (3): PO Calibration 92 4.4 Circuit Implementation 94 4.4.1 Overall Architecture 94 4.4.2 Circuit Description of Building Blocks (1): ILO 98 4.4.3 Circuit Description of Building Blocks (2): DCDL 101 4.5 Measurement Results 103 4.6 Summary 116 5 Conclusion 117 A Notes for PLL in the RCD 120 A.1 PLL as Zero-Delay Buffer 122 A.2 Practical Behavioral Simulation 123 A.3 Additional Measurement from ADVANTEST 124 Abstract (In Korean) 137박

Analysis of the characteristics of the environment and fish community in the Gwanggyo Lake Park area using the environmental DNA technique

This study aims to understand the relationship between the distribution of fish species in the two water ecosystems and the habitat factors according to the survey period targeting Gwanggyo Lake Park in the city. There are studies on the appearance and distribution of species by applying eDNA to freshwater ecosystems. However, in the domestic, streams are the target, and studies on the relationship between species distribution and habitat environment in two water environments are lacking. We conducted to analyze the species list and relationship with habitat factors using eDNA research in May and October at 21 points in Gwanggyo Lake Park, Suwon City, which were connected to lakes and streams. As a result, there was no species difference in the water environment according to the survey period. However, the total number of reads during the spawning season(May) was 3,126,482, which was more than double that after the spawning season(October). Tolerant species appeared in Woncheon Lake with a slow or stagnant flow, but there was no significant correlation between species and habitat factors depending on the survey period. On the other hand, intermediate and sensitive species appeared in the Woncheon stream with high flow. There was a significant correlation between the low temperature during the spawning season and the high dissolved oxygen content after the spawning season(P<0.001, Tem.: 20.7±2.6°C, DO: 8.6±1.7). It is expected that environmental DNA will be used to survey species and suggest monitoring methods according to the survey period.N

Assessing conservation priorities of unexecuted urban parks in Seoul using ecological network and accessibility analyses

This study aims to quantitatively evaluate the conservation priorities of unexecuted urban parks in Seoul both from an ecological and public perspective. To this end, two methodologies, ecological network analysis based on graph and circuit theory and accessibility analysis, were employed in order to assess ecological connectivity of and public accessibility to unexecuted parks, respectively. This study applied linkage-mapping methods (shortest path and current flow betweenness centrality) of connectivity analysis to an integrated map of landscape permeability. The population-weighted accessibility to unexecuted parks was measured based on a negative exponential distance decay function. As a result, for both ecological connectivity and accessibility, Gwanaksan, Suraksan, and Bulamsan urban natural parks are found to be the most important (rank 1-3) to be conserved. For these sites, inner park areas with conservation priorities for connectivity and accessibility were identified. The findings of the study can be used for giving conservation priority to the unexecuted urban parks in terms of long-term sustainable urban planning.OAIID:RECH_ACHV_DSTSH_NO:T201806605RECH_ACHV_FG:RR00200001ADJUST_YN:EMP_ID:A075721CITE_RATE:0DEPT_NM:조경·지역시스템공학부EMAIL:[email protected]_YN:NN

Feasibility of Environmental DNA Metabarcoding for Invasive Species Detection According to Taxa

효과적인 외래생물 관리 전략 수립을 위해서는 도입 및 확산 여부 평가를 위한 정기 모니터링이 요구된다. 환경 DNA (eDNA, environmental DNA) 메타바코딩은 높은 검출 민감도를 가지고 다수의 종을동시에 검출할 수 있어 외래생물의 출현 여부와 그 영향을 평가하는데 활발히 활용되고 있다. 국내에서는어류를 중심으로 메타바코딩의 적용 가능성 평가가 이루어지고 있으며 타 분류군에 대한 연구는 부족한 실정이다. 따라서 본 연구에서는 환경 DNA 메타바코딩을 활용한 국내 외래생물 탐지 가능성을 확인하고자했다. 분류군별 검출 가능성을 확인하기 위해 어류, 포유류, 조류, 양서류를 목표로 디자인 된 4가지 범용 프라이머(MiFish, MiMammal, Mibird, Amp16S)를 활용하여 대상종 검출 여부를 평가하였다. 그 결과, 총55개 지점 중 17개 지점(Trachemys scripta, 3개 지점; Cervus nippon, 3개 지점; Micropterus salmoides, 7개 지점; Rana catesbeiana, 4개 지점)에서 대상종의 서식이 확인되었다. 대상지 내 조밀한 지점 선정에도 생태적 특성을 반영한 검출 지점에 차이가 나타났다. 큰입배스와 붉은귀거북을 중심으로 외래생물이 출현이 생물 군집구조(종 풍부도, 풍부도, 다양도)에 미치는 영향을 비교한 결과, 외래생물이 서식하는 지점에서의 다양도가 더 높게 나타났다. 또한 외래생물 출현 지점에서 출현 종 수가 1~4종 추가 검출되었으며풍부도 또한 1.7배 높게 나타났다. 메타바코딩을 통한 외래생물 검출 결과 및 군집구조 비교는 eDNA를 통한 다량의 모니터링 데이터 구축이 다차원적 생태계 평가에 효율적으로 활용될 수 있음을 나타냈다. 또한환경의 인위적, 자연적 변화에 따른 생물상 변화를 관찰하고 자연생태 분야의 환경영향평가 등 현황 평가및 예측을 위한 주요한 기초자료로 활용 가능성을 제시하였다.N

Spatial Usage and Patterns of Corvus frugilegus after Sunrise and Sunset in Suwon Using Citizen Science

In Suwon, the overall hygiene of the city is threatened by the emergence of the rook(Corvus fugilegus) in the city. Rooks began to appear in November of 2016 and has continued to appear from November to March every year. In order to eradicate or to prepare an alternative habitat for rooks, this study aimed to identify the preferred habitat and specific environmental variables. Therefore, in this work, we aim to understand the predicted distribution of rooks in Suwon City with citizen science and through MaxENT, the most widely utilized habitat modeling using citizen science to analyze the preferred habitat of harmful tides appearing in urban areas. In this study, seven environmental variables were chosen: biotope group complex, building floor, vegetation, euclidean distance from farmland, euclidean distance from streetlamp, and euclidean distance from pole and DEM. Among the estimated models, after the time period of sunrise (08:00~18:00) the contribution percentage were as following: euclidean distance from arable land(39.2%), DEM(25.5%), euclidean distance from streetlamp(22.3%), euclidean distance from pole(7.1%), biotope group complex(4.9%), building floor(1%), vegetation(0%). In the time period after sunset(18:00~08:00) the contribution percentage were as following: biotope group complex(437.4%), euclidean distance from pole(26.8%), DEM(13.4%), euclidean distance from streetlamp(11.8%), euclidean distance from farmland(7.9%), building floor(1.4%), vegetation(1.3%).N