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A 70 MHz Temperature-Compensated On-Chip CMOS Relaxation Oscillator for Mobile Display Driver ICs
Kyunghoon Chung,Seong-Kwan Hong,Oh-Kyong Kwon 대한전자공학회 2016 Journal of semiconductor technology and science Vol.16 No.6
A 70 MHz temperature-compensated onchip CMOS relaxation oscillator for mobile display driver ICs is proposed to reduce frequency variations. The proposed oscillator compensates for frequency variation with respect to temperature by adjusting the bias currents to control the change in delay of comparators with temperature. A bandgap reference (BGR) is used to stabilize the bias currents with respect to temperature and supply voltages. Additional temperature compensation for the generated frequency is achieved by optimizing the resistance in the BGR after measuring the output frequency. In addition, a trimming circuit is implemented to reduce frequency variation with respect to process. The proposed relaxation oscillator is fabricated using 45 nm CMOS technology and occupies an active area of 0.15 mm<SUP>2</SUP>. The measured frequency variations with respect to temperature and supply voltages are as follows: (i) ±0.23% for changes in temperature from -30 to 75°C, (ii) ±0.14% for changes in VDD1 from 2.2 to 2.8 V, and (iii) ±1.88% for changes in VDD2 from 1.05 to 1.15 V.
A 70 MHz Temperature-Compensated On-Chip CMOS Relaxation Oscillator for Mobile Display Driver ICs
Chung, Kyunghoon,Hong, Seong-Kwan,Kwon, Oh-Kyong The Institute of Electronics and Information Engin 2016 Journal of semiconductor technology and science Vol.16 No.6
A 70 MHz temperature-compensated on-chip CMOS relaxation oscillator for mobile display driver ICs is proposed to reduce frequency variations. The proposed oscillator compensates for frequency variation with respect to temperature by adjusting the bias currents to control the change in delay of comparators with temperature. A bandgap reference (BGR) is used to stabilize the bias currents with respect to temperature and supply voltages. Additional temperature compensation for the generated frequency is achieved by optimizing the resistance in the BGR after measuring the output frequency. In addition, a trimming circuit is implemented to reduce frequency variation with respect to process. The proposed relaxation oscillator is fabricated using 45 nm CMOS technology and occupies an active area of $0.15mm^2$. The measured frequency variations with respect to temperature and supply voltages are as follows: (i) ${\pm}0.23%$ for changes in temperature from -30 to $75^{\circ}C$, (ii) ${\pm}0.14%$ for changes in $V_{DD1}$ from 2.2 to 2.8 V, and (iii) ${\pm}1.88%$ for changes in $V_{DD2}$ from 1.05 to 1.15 V.
Chung Kwon Kim,Jee Soo Park,Eunji Kim,Min-Kyun Oh,Yong-Taek Lee,Kyung Jae Yoon,Kyeung Min Joo,Kyunghoon Lee,박영숙 생화학분자생물학회 2022 BMB Reports Vol.55 No.10
Traumatic brain injury (TBI) is brain damage which is causedby the impact of external mechanical forces. TBI can lead to thetemporary or permanent impairment of physical and cognitiveabilities, resulting in abnormal behavior. We recently observedthat a single session of early exercise in animals with TBI improvedtheir behavioral performance in the absence of othercognitive abnormalities. In the present study, we investigatedthe therapeutic effects of continuous exercise during the earlystages of TBI in rats. We found that continuous low-intensityexercise in early-stage improves the locomotion recovery in theTBI of animal models; however, it does not significantly enhanceshort-term memory capabilities. Moreover, continuousearly exercise not only reduces the protein expression of cerebraldamage-related markers, such as Glial Fibrillary Acid Protein(GFAP), Neuron-Specific Enolase (NSE), S100β, Protein GeneProducts 9.5 (PGP9.5), and Heat Shock Protein 70 (HSP70), butit also decreases the expression of apoptosis-related protein BAXand cleaved caspase 3. Furthermore, exercise training in animalswith TBI decreases the microglia activation and the expressionof inflammatory cytokines in the serum, such as CCL20, IL-13,IL-1α, and IL-1β. These findings thus demonstrate that earlyexercise therapy for TBI may be an effective strategy in improvingphysiological function, and that serum protein levels are usefulbiomarkers for the predicition of the effectiveness of early exercisetherapy.
Chung Kwon Kim,Ji-Yoon Hwang,Tae Hee Hong,Du Man Lee,Kyunghoon Lee,남현,Kyeung Min Joo 생화학분자생물학회 2022 BMB Reports Vol.55 No.7
Narrowing of arteries supplying blood to the limbs provokescritical hindlimb ischemia (CLI). Although CLI results in irreversiblesequelae, such as amputation, few therapeutic options inducethe formation of new functional blood vessels. Based onthe proangiogenic potentials of stem cells, in this study, it wasexamined whether a combination of dental pulp stem cells(DPSCs) and human umbilical vein endothelial cells (HUVECs)could result in enhanced therapeutic effects of stem cells for CLIcompared with those of DPSCs or HUVECs alone. The DPSCs+HUVECs combination therapy resulted in significantly higherblood flow and lower ischemia damage than DPSCs or HUVECsalone. The improved therapeutic effects in the DPSCs+ HUVECsgroup were accompanied by a significantly higher number ofmicrovessels in the ischemic tissue than in the other groups. Invitro proliferation and tube formation assay showed that VEGFin the conditioned media of DPSCs induced proliferation andvessel-like tube formation of HUVECs. Altogether, our resultsdemonstrated that the combination of DPSCs and HUVECs hadsignificantly better therapeutic effects on CLI via VEGF-mediatedcrosstalk. This combinational strategy could be used to developnovel clinical protocols for CLI proangiogenic regenerative treatments.
Bongsub Song,Kyunghoon Kim,Junan Lee,Jinil Chung,Youngjung Choi,Jinwook Burm IEEE 2014 IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS PART 2 E Vol.61 No.9
<P>A 13.5-mW 10-Gb/s four-level pulse-amplitude modulation (4-PAM) serial link transmitter is presented. To improve the power efficiency, a voltage-mode 4-PAM driver is proposed. It consists of voltage-scaled pull-up and pull-down networks, instead of conventional current switching networks. Not employing a tail current source, the proposed 4-PAM driver achieves the higher output voltage swing and lower power dissipation than conventional 4-PAM drivers. As a result, the proposed 4-PAM transmitter implemented in a 0.13-μm CMOS process achieved 10-Gb/s data rate with only 13.5-mW power dissipation.</P>
An Antiharmonic, Programmable, DLL-Based Frequency Multiplier for Dynamic Frequency Scaling
Sunghwa Ok,Kyunghoon Chung,Jabeom Koo,Chulwoo Kim IEEE 2010 IEEE transactions on very large scale integration Vol.18 No.7
<P>This paper describes a new delay-locked loop (DLL)-based frequency multiplier, which includes a lock controller and a phase detector to solve the false lock problem and overcome the limited locking range of conventional DLLs. By using the multiple clock phases of the DLL, the lock controller is able to indicate whether the delay time of the VCDL is within the correct locking range or not. A differentially controlled edge combiner is also proposed for the frequency multiplication. The antiharmonic DLL-based frequency multiplier, implemented in a 0.18-μ.m CMOS process, occupies an active area of 0.043 mm<SUP>2</SUP>, and dissipates 36.7 mW at 1.7 GHz. The measured root mean square jitter and peak-to-peak jitter for the multiplied output clock at 1.7 GHz are 2.64 and 16.8 ps, respectively.</P>
티타늄 합금의 연마제 위터 제트절단에 의한 절단표면 특성
진윤호(Yunho Jin),정남용(Namyong Chung),김경훈(Kyunghoon Kim) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Abrasive waterjet (AWJ) can provide a more effective means fur precision of difficult -to-machining materials such as ceramics and titanium alloys. The present study is focused on the surface roughness of abrasive waterjet cut surfaces. This paper investigated theoretical and experimental surface characteristics associated with abrasive water jet cutting of titanium alloy Gr2. it is shown that the proper variations of several cutting parameters such as waterjet cutting pressure, cutting speed and cutting depth improve the roughness and characteristics on specimen surfaces produced by AWJ cutting. From the experimental results by AWJ cutting of titanium alloy Gr2, the optimal cutting conditions to improve the surface roughness and precision were proposed and discussed.
KAAACI Guidelines for Allergen Immunotherapy
Lee Hwa Young,이상민,강성윤,Kim Kyunghoon,Kim Ju Hee,Ryu Gwanghui,Min Jin-Young,Park Kyung Hee,Park So-Young,Sung Myongsoon,Lee Youngsoo,Yang Eun Ae,Jee Hye Mi,Ha Eun Kyo,Shin Yoo Seob,Chung Eun Hee,Choi Su 대한천식알레르기학회 2023 Allergy, Asthma & Immunology Research Vol.15 No.6
Allergen immunotherapy (AIT) is a causative treatment for various allergic diseases such as allergic rhinitis, allergic asthma, and bee venom allergy that induces tolerance to offending allergens. The need for uniform practice guidelines in AIT is continuously growing because of the increasing discovery of potential candidates for AIT and evolving interest in new therapeutic approaches. This guideline is an updated version of the Korean Academy of Asthma Allergy and Clinical Immunology recommendations for AIT published in 2010. This updated guideline proposes an expert opinion by allergy, pediatrics, and otorhinolaryngology specialists with an extensive literature review. The guideline deals with basic knowledge and methodological aspects of AIT, including mechanisms, clinical efficacy, patient selection, allergens extract selection, schedule and doses, management of adverse reactions, efficacy measurements, and special consideration in pediatrics. The guidelines for sublingual immunotherapy will be covered in detail in a separate article.