• Journal of Power System Engineering
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• v.6 no.4
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• pp.81-87
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• 2002

The modelling and controller design of the EMV(electro-magnetic valve) for vehicle engine are considered in this paper. For the analysis and controller design, the governing equation of the EMV system is derived. For a good performance of the system, the start control, the holding control and the swing control are included in the controller design of the EMV system. In order to reduce landing speed of the valve, the on-time delay control which mainly come from the optimal control theory is employed. In order to reduce the power consumption of the system, the pick-up and hold operation has been used for the magnetic coil. The simulation and experimental results are presented to show the validity of the control method.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.5
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• pp.511-518
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• 2021

To accelerate a launch mass with a low level of pressure as possible in a railgun, it is required to hold supplied current nearly constant during launch phase. We obtained the discharging conditions for required current shaping by modeling and analysis of circuit equations coupled to acceleration equation of the launch mass. The acceleration characteristics of the railgun in the conditions were analyzed by comparing experimental and theoretical results.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.70-72
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• 2020

본 논문에서는 동작 영역 감지 회로를 이용한 LLC 컨버터의 홀드-업 시간 연장 기법을 제안한다. LLC 컨버터는 주로 소프트 스위칭이 가능한 인덕티브 영역에서 동작하며, 커패시티브 영역에서의 동작을 방지하기 위해서 최대 전압 이득을 가지는 스위칭 주파수보다 충분히 높은 주파수까지만 동작시킨다. 그 결과, LLC 컨버터가 가지는 최대 전압 이득을 활용하지 못하기 때문에, 입력 전압 범위가 좁아져 홀드-업 시간이 줄어들게 된다. 본 논문에서는 LLC 컨버터의 동작 영역을 감지하여, 최대 전압 이득을 가지는 스위칭 주파수까지 동작시킴으로서 홀드-업 시간을 최대로 가지게 한다. 제안된 기법을 통해 홀드-업 시간이 증가하고, 링크 커패시터의 부피를 감소시킬 수 있다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.219-225
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• 2014

The New efficient Mux-based scan latch cell design and scan test of LOS/LOC modes are proposed for detection of delay faults in digital logic circuits. The proposed scan cell design can support LOS(Launch-off-Shift) and LOC(Launch-off-Capture) tests with high fault coverage and low scan power and it can alleviate the problem of the slow selector enable signal and hold signal by supporting the logic capable of switching at the operational clock speeds. Also, it efficiently controls the power dissipation of the scan cell design during scan testing. Functional operation and timing simulation waveform for proposed scan hold cell design shows improvement in at-speed test timing in both test modes.

• Journal of Advanced Navigation Technology
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• v.21 no.6
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• pp.651-658
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• 2017

There were many studies on the development of radiation measuring instruments to detect the presence of radiation. In particular, the signal processing method and treatment without loss of the detection signal are very important. The common feature for these studies is the peak-hold method that keeps the peak value of input signal uniform for a short time, readouts its value, discharges electrical value, and then waits for next signal. We propose the new methodology to capture the pulse peak value from the radiation detector and read the value directly other than peak-hold method. This method has merit of accurate reading the input signal pulse peak value without complicate process of holding for a period or initializing of input signal, and then be verified to be adequate through simulation of actual example.

• The Journal of the Acoustical Society of Korea
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• v.18 no.2
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• pp.53-60
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• 1999

In this paper, it is proposed to a new architecture of CMOS IADC(Current-Mode Analog-to-Digital Converter) using 1.5-bit bit cell of which consists a CSH(Current-Mode Sample-and-Hold) and CCMP(Current-Mode Comparator). In order to guarantee the entire linearity of IADC, the CSH is designed to cancel CFT(Clock Feedthrough) whose resolution is to meet at the least 9-bit which is placed in the front-end of each bit cell. In the proposed IADC, digital correction logic is simplified and power consumption is reduced because bit cell of each stage needs two latch CCMP. Also, it is available for a mixed-mode integrated circuit because all of block is designed with only MOS transistor. With the HYUNDAI 0.8㎛ CMOS parameter, the HSPICE simulation results show that the proposed IADC can be operated at 20Ms/s with SNR of 43 dB with which is satisfied 7-bit resolution for input signal at 100 ㎑, and its power consumption is 27㎽.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.1
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• pp.8-14
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• 2009

A lamp which is currently employed to LCD(Liquid Crystal Display) Backlight is almost CCFL(Cold Cathod Fluorescent Lamp) and EEFL(External Electrode Fluorescent Lamp). However, the use of these lamps is being restricted as RoHS(the Restriction of the use of certain Hazardous Substances in electrical and electronic equipment) regulation is gradually reinforced. According to this situation, the manufacturing of a lamp which doesn't use mercury is unescapable. Moreover, LCD TV has a defect which take place Motion Blur phenomenon due to response time of LC(Liquid Crystal), and Hold-type characteristic which only exists in LCD differently to CRT, PDP. In this paper, an inverter is proposed to drive a plane light source lamp which is not containing mercury. Driving circuit of proposed inverter is simple because the number of semiconductor device and magnetic device is reduced by using forward topology. Also, Motion Blur phenomenon is decreased by dividing the plane light source lamp to six block along vertical direction, and scanning. Finally, we proved usefulness of proposed inverter through experiment.

• International Journal of Aerospace System Engineering
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• v.9 no.2
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• pp.1-9
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• 2022

The NEA release mechanism is used to provide restraint and release functions with low shock for critical deployment operations on solar arrays after launch. The GK3 solar array consists of 2 wings and 6 hold down points per panel. The NEA SSD9103S1 is a part of the GK3 solar array hold-down and release mechanism. Each NEA unit is equipped with two Z-diodes which provide power to a NEA unit connected in series after actuation of the fuse wire. This paper presents the hot firing test results of a quadrature NEA SSD9103S1 configuration. One output powers a maximum of 4 NEA SSD9103S1 units simultaneously. The necessary actuation pulse duration has been determined to meet margin requirement for thermal energy of minimum 4. Actuation thermal energy difference is about 6.6% between each half of two fired serial NEAs. Thermal energy margin at worst case is minimum 5.9 in case of an actuation pulse duration of 500 ms. Two series Zener impedance depend on current applied has been characterized by an additional actuation after all fuse wires are open circuit. Total number of actuation commands to the GK3 NEA unit reduce drastically from 24 in case of single NEA configuration down to 8 in case of parallel and quadrature NEA configurations. It can be accommodated by the existing HP2U Pyro design without any impact.

• Journal of Biosystems Engineering
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• v.24 no.2
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• pp.115-122
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• 1999

Because of their small mass, volume, solid state construction and long life, light-emitting diodes(LEDs) hold promises as a lighting source for intensive plant production system. Spectral characteristics and light intensity of LEDs were tested to investigate their feasibility as artificial lighting sources for growth and morphogenesis control in transplant production system. Blue, green, and red LEDs had a peak-emission wavelength at 442nm, 522nm, and 673nm, respectively. Their half width defined as the difference between upper and lower wavelength in the intensity equivalent to 50% of the maximum intensity showed 26nm, 41nm, and 74nm, respectively. Photosynthetic photon flux(PPE) at the distance of 9cm under the LEDs array was measured as $235{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ for red, $109{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ for green, and $75{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ for blue LEDs. At the same distance, green LEDs had the illuminance of 13,0001x, nine to ten times higher than those of red and blue LEDs. Red, green, and blue LEDs at a distance of 9cm had the irradiance of $46W{\cdot}m^{-2},\;19W{\cdot}m^{-2},\;8W{\cdot}m^{-2}$, respectively. Light intensity of blue, green, and red LEDs increased linearly in proportion to the magnitude of the current applied to the operating circuit. Thus the light intensity of LEDs was controlled by the applied current in operating circuit.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.5
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• pp.529-538
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• 1992

Recently, image signal processing techniques for HDTV signal have been drastically developed. This kind of skill improvement on signal processing need specific memory device for video signal. in this paper, data latch scheme which implements CMOS flip-flop to hold Information from in-put strobe and new reading method is devised to attain a proper access time suitable for HDTY signal. Compared with conventional write scheme, data latch method has two procedures to complete write operation : bit line write and storage cell write, enabling concurrent I /0 operation at the same address. Also, fast read access is possible through the method similar to static column mode and the separated read word line.