A PVT-Robust and Low-Jitter Ring-VCO-Based Injection-Locked Clock Multiplier With a Continuous Frequency-Tracking Loop Using a Replica-Delay Cell and a Dual-Edge Phase Detector

Choi, Seojin,Yoo, Seyeon,Lim, Younghyun,Choi, Jaehyouk IEEE 2016 IEEE journal of solid-state circuits Vol.51 No.8

<P>A low-jitter, ring-type voltage-controlled oscillator (VCO)-based injection-locked clock multiplier (ILCM) with a continuous frequency-tracking loop (FTL) for process-voltage-temperature (PVT)-calibration is presented. Using a single replica-delay cell of the VCO that provides the intrinsic phase information of the free-running VCO, the proposed FTL can continuously track and correct frequency drifts. Therefore, the proposed ILCM can calibrate real-time frequency drifts due to voltage or temperature variations as well as static frequency deviations due to process variations. Since the FTL provided an additional filtering of in-band VCO noise, the ILCM was able to achieve excellent jitter performance over the PVT variations, while it was based on a ring-VCO. The proposed ILCM was fabricated in a 65 nm CMOS process. When injection locked, the RMS-jitter integrated from 10 kHz to 40 MHz of the 1.20 GHz output signal was 185 fs. The proposed PVT-calibrator regulated the degradations of jitter to less than 5% and 7% over temperatures and supply voltages, respectively. The active area was 0.06 mm(2) and total power consumption was 9.5 mW.</P>

An Ultra-Low-Jitter 22.8-GHz Ring-<i>LC</i>-Hybrid Injection-Locked Clock Multiplier With a Multiplication Factor of 114

Choi, Seojin,Yoo, Seyeon,Lee, Yongsun,Jo, Yongwoo,Lee, Jeonghyun,Lim, Younghyun,Choi, Jaehyouk IEEE 2019 IEEE journal of solid-state circuits Vol.54 No.4

<P>An ultra-low-jitter, ring-<I>LC</I> -hybrid injection-locked clock multiplier (ILCM) is presented to achieve a high multiplication factor of 114. The proposed hybrid ILCM cascades a ring-type voltage-controlled oscillator (VCO)-based ILCM and an <I>LC</I>-type VCO-based ILCM. Using a dual-purpose frequency calibrator (DPFC) that can continuously calibrate the frequency drifts of the two VCOs, concurrently, the proposed ILCM can maintain excellent jitter performance against process-voltage-temperature (PVT) variations. Since the DPFC eliminates the use of an additional calibrator and operates at a very low frequency, it can reduce the expenditures for silicon and power. The proposed ILCM was fabricated in a 65-nm CMOS process. The RMS jitter of the 22.8-GHz output, integrated from 1 kHz to 100 MHz, was 153 fs, and the DPFC restricted its variations due to variations in temperatures and supply voltages to less than 180 fs. The proposed ILCM achieved the power efficiency of 0.32 mW/GHz. The active area was 0.2 mm<SUP>2</SUP>. The total power consumption was 7.4 mW, but the DPFC consumed only 400 <TEX>$\mu \text{W}$</TEX>.</P>

실시간 환경변화에도 안정적인 Injection-Locking 기반 초저잡음 고주파신호 생성기 설계

최재혁(Jaehyouk Choi) 대한전자공학회 2017 대한전자공학회 학술대회 Vol.2017 No.6

For generating an ultra-low-noise high-frequency clock signal, an injection-locked clock generator (ILCG) is a promising solution. However, the vulnerability of its noise performance to PVT variations is a critical problem that has limited its popularity in practical applications. This paper presents circuit solutions for an ILCG, which can calibrate the real-time frequency drifts due to PVT variations and secure low-noise performance.

가동보와 소수력발전 연계시스템의 규모 결정을 위한 최적화 모형 연구

이재혁 ( Jaehyouk Lee ),김선주 ( Sunjoo Kim ),김필식 ( Philshik Kim ),권형중 ( Hyungjoong Kwon ),최범준 ( Bumjun Choi ) 한국농공학회 2013 한국농공학회 학술대회초록집 Vol.2013 No.-

전 세계적으로 신재생에너지에 대한 요구가 증가하고 있으며 하천에서 가동보를 이용한 저낙차 소수력 발전에 대한 관심이 급증하고 있다. 특히, 우리나라와 같이 하천 폭이 크고 수량이 확보된 경우 소수력 발전에 유리함에도 불구하고 선진국에 비해 소수력 발전 이용률이 현저하게 낮은 실정이다. 본 연구는 가동보와 소수력발전 연계시스템의 규모 결정을 위한 최적화 모형(Weir-HydroGEN System)을 개발하는 것이 목적이며, 개발된 모형을 국내 대상 지구에 적용함으로서 모형을 검증하고, 검증된 모형을 국내외에 10개 지역에 적용하여 가동보와 소수력발전 연계시스템 구축에 대한 타당성을 제시하였다. 모형의 검증을 위해서 고무보를 이용하여 소수력 발전을 운영하고 있는 은동보(대전), 서리보(강원도), 원통보(강원도)에 지구에 적용하였다. 가동보를 이용한 소수력 발전은 발전사용수량 인자에 의해 그 규모가 결정되고 총 투자비용의 회수기간이 달라지므로 발전사용수량의 산정을 세 가지 시나리오 즉, 평수량 (S1), 갈수량의 3배 (S2), 유황곡선의 26% (S3)로 산정하여 모형을 적용하였다. 경제성 분석을 위하여 모형을 적용한 결과, 은동보는 35년 동안의 모의 운영에도 불구하고 발생 이윤이 총 투자비용을 초과하지 못하여 경제적인 타당성을 확인하지 못하였고, 원통보의 경우 S3 시나리오에서 B/C 지표가 1을 상위하고, 서리보의 경우 S1 시나리오 및 S3 시나리오에서 B/C 지표가 양호하게 산정되었다. 검증된 모형을 이용하여 국내ㆍ외 10개 지구 (국내 5개 지구 : 선교보, 무태보, 하양보, 영천제1가동보, 안림천보, 국외 5개 지구 : West Buxton, East Toba, Stave River, Bear Creek, Kapuskasing)에 적용하여 발전시설의 규모 결정 및 경제성 분석을 수행하였다. 모형의 국내 적용 결과, 무태보를 제외한 모든 보에서 B/C의 값이 1이하로 나타나 소수력발전의 입지조건에 적합하지 않으며, 무태보에서 B/C값이 1.06, 투자비 회수기간은 24년으로 낮게 나타났지만 소수력 발전 설비의 입지 가능성은 확보된 것으로 분석되었다. 모형의 국외 적용 결과, West Buxton보와 Bear Creek보는 각각 B/C값이 1.96, 1.74, 투자비 회수기간은 6년, 7년으로 분석되었고, Stave River보와 East Toba보는 각각 B/C값이 3.25, 3.14, 투자비 회수기간은 3년, 4년으로 매우 높은 경제성을 확보하였고, Kapuskasing보는 B/C값이 1을 넘지 못하여 충분한 경제성을 확인하지 못하였다. 이상의 적용 결과로 미루어 볼 때, 국내 하천은 최근 시기적으로 부각되고 있는 에너지 부족 현상을 대처할 수 있는 소수력 발전 부존량을 보유하고 있으며 또한, 경제성이 확보된 것으로 분석되었다. 국외의 경우에도 가동보를 이용한 소수력 발전 활용성이 확인되었으며 특히, 하천수량이 풍부하고 전력 단가가 상대적으로 고가인 동남아시아와 같은 개도국에 적용할 경우 그 효과가 제고될 것으로 판단된다.

A Low-Integrated-Phase-Noise 27–30-GHz Injection-Locked Frequency Multiplier With an Ultra-Low-Power Frequency-Tracking Loop for mm-Wave-Band 5G Transceivers

Yoo, Seyeon,Choi, Seojin,Kim, Juyeop,Yoon, Heein,Lee, Yongsun,Choi, Jaehyouk IEEE 2018 IEEE journal of solid-state circuits Vol.53 No.2

<P>An ultra-low-phase-noise injection-locked frequency multiplier (ILFM) for millimeter wave (mm-wave) fifth-generation transceivers is presented. Using an ultra-low-power frequency-tracking loop (FTL), the proposed ILFM is able to correct the frequency drifts of the quadrature voltage-controlled oscillator of the ILFM in a real-time fashion. Since the FTL is monitoring the averages of phase deviations rather than detecting or sampling the instantaneous values, it requires only 600 <TEX>$\mu \text{W}$</TEX> to continue to calibrate the ILFM that generates an mm-wave signal with an output frequency from 27 to 30 GHz. The proposed ILFM was fabricated in a 65-nm CMOS process. The 10-MHz phase noise of the 29.25-GHz output signal was −129.7 dBc/Hz, and its variations across temperatures and supply voltages were less than 2 dB. The integrated phase noise from 1 kHz to 100 MHz and the rms jitter were −39.1 dBc and 86 fs, respectively.</P>

A Theoretically Sound Approach to Analog Circuit Sizing

Eunji Lim,Jaehyouk Choi,Youngmin Kim 대한전자공학회 2018 Journal of semiconductor technology and science Vol.18 No.2

We consider the problem of determining the sizes of electrical components in analog circuits, such as operational amplifiers, that maximize a primary performance measure while satisfying some conditions on secondary performance measures. We propose a method that uses a circuit simulator, such as SPICE, to evaluate the performance measures exactly and updates the sizes of the electrical components iteratively using an optimization procedure, which is a variant of the Lagrangian method. The proposed approach guarantees convergence to a local optimal solution under mild conditions. Numerical results demonstrate that the proposed method finds optimal sizes successfully in various circuits including one-stage and two-stage operational amplifiers, a voltage-controlled oscillator, and an inverter chain.

An Ultra-Low Power and Compact <tex> $LC$</tex>-Tank-Based Frequency Tripler Using Pulsed Input Signals

Seyeon Yoo,Seojin Choi,Taeho Seong,Jaehyouk Choi THE INSTITUTE OF ELECTRICAL ENGINEERS 2016 IEEE Microwave and Wireless Components Letters Vol. No.

<P>This letter presents a low power and compact area LC-tank-based frequency multiplier. In the proposed architecture, the input signals have a pulsed waveform that involves many high-order harmonics. Using an LC-tank that amplifies only the target harmonic component, while suppressing others, the output signal at the target frequency can be obtained. Since the core current flows for a very short duration, due to the pulsed input signals, the average power consumption can be dramatically reduced. Effective removal of spurious tones due to the damping of the signal is achieved using a limiting amplifier. In this work, a prototype frequency tripler using the proposed architecture was designed in a 65 nm CMOS process. The power consumption was 950 mu W, and the active area was 0.08 mm(2). At a 3.12 GHz frequency, the phase noise degradation with respect to the theoretical bound was less than 0.5 dB.</P>

A Reconfigurable Multiphase <inline-formula> <tex-math notation='TeX'> $LC$ </tex-math></inline-formula>-Ring Structure for Programmable Frequency Multiplication

Donguk Kim,Subin Choi,Jaehyouk Choi,Jae Joon Kim IEEE 2015 IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS PART 2 E Vol.62 No.1

<P>This brief presents a reconfigurable LC-ring structure and a programmable millimeter-wave low-power frequency multiplier that were combined together to achieve a maximum power-saving effect of 73% depending on operation modes. The proposed multiphase LC ring is reconfigurable to change the number of stages and thereby minimize current consumption depending on the number of phases necessary in an application. The programmable multiplier is implemented to reduce its current consumption by 82% through an inverter-type input circuit. A millimeter-wave frequency multiplier prototype, including the reconfigurable multiphase LC ring, was fully integrated in a 65-nm CMOS process and experimentally verified to provide programmable frequency multiplication over triple frequency bands of 12.6-15.2, 25.2-30.4, and 50.4-60.8 GHz, utilizing a 6.3 to 7.6-GHz multiphase LC ring.</P>

Ultralow In-Band Phase Noise Injection-Locked Frequency Multiplier Design Based on Open-Loop Frequency Calibration

Taeho Seong,Yongsun Lee,Jaehyouk Choi IEEE 2014 IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS PART 2 E Vol.61 No.9

<P>A new design methodology is proposed for an ultralow in-band phase noise injection-locked frequency multiplier (ILFM) based on open-loop frequency calibration. The prototype ILFM was designed and fabricated in the 65-nm CMOS process. Using an open-loop calibrator without a real-time monitoring loop, the ILFM achieved excellent in-band phase noise with low power consumption and a small silicon area. Following the design procedure based on the phase noise analysis, the proposed ILFM showed that the open-loop calibrator was capable of overcoming phase noise degradation due to process-voltage-temperature variations. The output frequency was 3.0 GHz when the oscillator was injection locked by the 15th harmonic of the 200-MHz reference clock. The in-band phase noise performance was -117.0, -122.6, and -124.5 dBc/Hz at 10-, 100-, and 1-MHz offsets, respectively. The total active area was 0.19 mm<SUP>2</SUP>, and the power consumption was 8.1 mW.</P>

고무보의 내구성 증대를 위한 방탄/방검 고무시트 개발

김필식 ( Philshik Kim ),이재혁 ( Jaehyouk Lee ),최범준 ( Bumjun Choi ),박현준 ( Hyunjun Park ),권형중 ( Hyungjoong Kwon ) 한국농공학회 2011 한국농공학회 학술대회초록집 Vol.2011 No.-

A lot of small dams installed in stream are generally used to control water level and to manage water resources. The type of these dams is mostly fixed dam which has caused a gradual decline in the water quality and river environment, because the fixed dam would lead to sedimentation and flow retention. For this reason, demand for the movable dams which can regulate the stream flow continues to expand and many related studies are being carried out to reduce stream pollution and sedimentation. The rubber dam which is one of the types of movable dam is very easy to install and maintain. However, if the rubber sheet, which has long-term durability (over 30 years) without artificial detriments and natural disasters, would be damaged by any reason, it could cause the water pollution in all directions and also it should be too hard to fix the rubber sheet with high expense as well. In order to secure water resources and conserve river environment, an adequate provision against these damages will be necessary to protect the rubber sheet. In this study, we have fully comprehended the causes of maintenance based on a case study. An abrasion indicator layer was developed and folded between the rubber sheets for early warning signs of abrasion. A bullet- and sword- proof rubber sheet was developed to protect the rubber dam from artificial detriments and natural disasters. We have achieved an economic analysis of these developed techniques.