• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.1
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• pp.110-116
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• 2016

This paper describes 1.2-V 5-Gb/s scalable low voltage signaling(SLVS) differential transmitter(TX) with a digital impedance calibration and equalizer. The proposed transmitter consists of a phase-locked loop(PLL) with 4-phase output clock, a 4-to-1 serializer, a regulator, an output driver, and an equalizer driver for improvement of the signal integrity. A pseudo random bit sequence generator is implemented for a built-in self-test. The proposed SLVS transmitter provides the output differential swing level from 80mV to 500mV. The proposed SLVS transmitter is implemented by using a 65-nm CMOS with a 1.2-V supply. The measured peak-to-peak time jitter of the implemented SLVS TX is about 46.67 ps at the data rate of 5Gb/s. Its power consumption is 1.88 mW/Gb/s.

• Journal of Energy Engineering
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• v.24 no.3
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• pp.6-12
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• 2015

The welding technology has been used in almost all industries such as automotive, shipbuilding, power plants and industrial machinery. In this study, the design and implementation of PLC $CO_2$ welding automation system were investigated. For these purposes, the structure analysis for driving supporter was performed and specification of automatic voltage regulator, mutual interface of system and circuit diagram were designed in order to contrive power-saving system. As the results, the stability of design for driving supporter could be convinced by numerical analysis and PLC automatic welding system was suitable for welding automation of structural-manufacturing factory capable of producing various and small amount products. Therefore, it was confirmed that PLC $CO_2$ welding automation system could contribute to productivity, stable quality and power-saving.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.4
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• pp.26-33
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• 2010

This paper presents a multi-channel capacitive touch sensing unit for SoC applications. This unit includes a simple common processing unit and switch array to detect the touch sensing input by capacitive-time(C-T) conversion method. This touch sensor ASIC is designed based on the Capacitive-Time(C-T) conversion method to have advantages of small current and chip area, and the minimum resolution of the unit is 41 fF per count with the built-in sensing oscillator, LDO regulator and $I^2C$ for no additional external components. This unit is implemented in 0.18 um CMOS process with dual supply voltage of 1.8 V and 3.3 V. The total power consumption of the unit is 60 uA and the area is 0.26 $mm^2$.

• Proceedings of the Korean Biophysical Society Conference
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• 2003.06a
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• pp.44-44
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• 2003

$BK_{Ca}$ channels were suggested to contain one or more domains of the ‘regulator of K+ conductance’(RCK) in their cytosolic carboxyl termini (Jiang et al.2001). It was also shown that the RCK domain in mammalian $BK_{Ca}$ channels might sense the intracellular $Ca^{2+}$ with a low affinity (Xia et al. 2002). We aligned the amino acid sequence of the $\alpha$-subunit of rat $BK_{Ca}$ channels (rSlo) with known RCK domains and identified a second region exhibiting about 50％ homology. This putative domain, RCK2, contains the characteristic amino acids conserved in other RCK domains. We wondered whether this second domain is involved in the domain-domain interaction and the gating response to intracellular $Ca^{2+}$ for rSlo channel, as revealed in the structure of RCK domain of E. coli channel (Jiang et al.2001). In order to examine the possibility, site-directed mutations were introduced into the RCK2 domain of rSlo channel and the mutant channels were expressed in Xenopus oocytes for functional studies. One of such mutation, G772D, in the putative nucleotide-binding domain resulted in the enhanced $Ca^{2+}$ sensitivity and the channel gating of rSlo channel. These results suggest that this region of $BK_{Ca}$ channels is important for the channel gating and may form an independent domain in the cytosolic region of $BK_{Ca}$ channels. In order to obtain the mechanistic insights of these results, G772 residue was randomly mutagenized by site-directed mutagenesis and total 17 different mutant channels were constructed. We are currently investigating these mutant channels by electrophysiological techniques.ical techniques.

• The Korean Journal of Physiology and Pharmacology
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• v.22 no.3
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• pp.277-289
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• 2018

The exponential increase in the use of mobile communication has triggered public concerns about the potential adverse effects of radiofrequency electromagnetic fields (RF-EMF) emitted by mobile phones on the central nervous system (CNS). In this study, we explored the relationship between calcium channels and apoptosis or autophagy in the hippocampus of C57BL/6 mice after RF-EMF exposure with a specific absorption rate (SAR) of 4.0 W/kg for 4 weeks. Firstly, the expression level of voltage-gated calcium channels (VGCCs), a key regulator of the entry of calcium ions into the cell, was confirmed by immunoblots. We investigated and confirmed that pan-calcium channel expression in hippocampal neurons were significantly decreased after exposure to RF-EMF. With the observed accumulation of autolysosomes in hippocampal neurons via TEM, the expressions of autophagy-related genes and proteins (e.g., LC3B-II) had significantly increased. However, down-regulation of the apoptotic pathway may contribute to the decrease in calcium channel expression, and thus lower levels of calcium in hippocampal neurons. These results suggested that exposure of RF-EMF could alter intracellular calcium homeostasis by decreasing calcium channel expression in the hippocampus; presumably by activating the autophagy pathway, while inhibiting apoptotic regulation as an adaptation process for 835 MHz RF-EMF exposure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.6
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• pp.2747-2753
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• 2011

In this paper, a PWM current-mode DC-DC boost converter for mobile phone flash application has been proposed. The converter which is operated with 5 Mhz high switching frequency is capable of reducing mounting area of passive devices such as inductor and capacitor, consequently is suitable for compact mobile phones. This boost converter consists of a power stage and a control block. Circuit elements of the power stage are inductor, output capacitor, MOS transistors and feedback resistors. Meanwhile, the control block consists of pulse width modulator, error amplifier, oscillator etc. Proposed boost converter has been designed and verified in a $0.5\;{\mu}m$ 1-poly 2-metal CMOS process technology. Simulation results show that the output voltage is 4.26 V in 3.7 V input voltage, output current 100 mA which is larger than 25 ~ 50 mA in conventional 500 Khz driven converter when the duty ratio is 0.15.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.10
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• pp.2237-2246
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• 2012

A bias circuit required for an oral sensor is manufactured inside the oral sensor chip to reduce its size and cost. The proposed DC-DC converter supplies the required reference and bias currents for their corresponding regulators by using IREF of the reference current generator. Their target voltages of the voltage regulators are regulated by the negative mechanism by generating their reference voltages required for their corresponding regulators. In addition, a constant current IB0/IB1 is supplied by being mirrored by a current mirror ratio and then VREF is generated. It is confirmed by measurements that the average volatge, ${\sigma}$, and $4{\sigma}$ of the designed DC-DC converter for intra oral sensors with a $0.18{\mu}m$ X-ray CMOS process are within their required ranges. And the line-pair pattern image shows a high-resolution characteristic without blurring. Also, a good oral image can be obtained.

• 전자공학회논문지 IE
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• v.46 no.4
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• pp.1-7
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• 2009

The final goal of ITS and ETC will be to improve the traffic efficiency and mobile safety without new road construction. DSRC system is emerging nowadays as a solution of them. China DSRC standard which was released in May 2007 has low bit rate, short message and simple MAC control. The DSRC system users want a long lifetime over 1 year with just one battery. In this paper, we propose the SoC of very low power consumption architecture. Several digital logic concept and analog power control logics were used for very low power consumption. The SoC operation mode and clock speed, operation voltage range, wakeup signal detector, analog comparator and Internal Voltage Regulator & External Power Switch were designed. We confirmed that the SoC power consumption is under 8.5mA@20Mhz, 0.9mA@1Mhz in active mode, and under 5uA in power down mode, by computer simulation. The design of SoC was finished on Aug. 2008, and fabricated on Nov. 2008 with $0.18{\mu}m$ CMOS process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5541-5549
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• 2015

This paper introduces a safer and more power efficient heater by using induction heating, to apply to the semiconductor wafer fabrication exhaust gas cleaning system. The exhaust gas cleaning system is currently made with filament heater that generates an endothermic reaction of N2 gas for the removal of moisture. Induction theory, through the bases of theoretical optimization and electronic implementation, is applied in the design of the induction heater specifically for the semiconductor wafer exhaust system. The new induction heating design provides a solution to the issues with the current energy inefficient, unreliable, and unsafe design. A robust and calibrated design of the induction heater is used to optimize the energy consumption. Optimization is based on the calibrated ZVS induction circuit design specified by the resonant frequency of the exhaust pipe. The fail-safe energy limiter embedded in the system uses a voltage regulator through the feedback of the MOSFET control, which allows the system performance to operate within the specification of the N2 Heater unit. A specification and performance comparison from current conventional filament heater is made with the calibrated induction heater design for numerical analysis and the proof of a better design.

• Journal of the Korean Institute of Gas
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• v.25 no.3
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• pp.27-38
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• 2021

We devised the system to automatically shutdown the boiler and to fundamentally block the harmful gases, including carbon monoxide, into the indoor when the exhaust system swerves: (1) The discharge pressure of the exhaust gas decreases when the exhaust pipe is disconnected. The monitoring system of the exhaust pipe is implemented by measuring the output voltage of APS(Air Pressure Sensor) installed to control the amount of combustion air. (2) The operating software was modified so that when the system recognizes the fault condition of a flue pipe, the boiler control unit displays the fault status on the indoor regulator while shutting down the boiler. In accordance with the ventilation facility standards in the "Rules for Building Equipment Standards" by the Ministry of Land, Infrastructure and Transport, experiments were conducted to ventilate indoor air. When carbon monoxide leaked in worst-case scenario, it was possible to prevent poisoning accidents. However, since 2013, the number of indoor air exchange times has been mitigated from 0.7 to 0.5 times per hour. We observed the concentration exceeding TWA 30 ppm occasionally and thus recommend to reinforce this criterion. In conclusion, if the flue pipe fault detection and the indoor air ventilation system are introduced, carbon monoxide poisoning accidents are expected to decrease significantly. Also when the manufacturing and inspection steps, the correct installation and repair are supplemented with the user's attention in missing flue, it will be served to prevent human casualties from carbon monoxide poisoning.