• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.7
• /
• pp.1235-1242
• /
• 2008

In this paper, x-ray image sensor of photon counting type having a $32{\times}32$ pixel array is designed with $0.18{\mu}m$ triple-well CMOS process. Each pixel of the designed image sensor has an area of loot $100{\times}100\;{\mu}m2$ and is composed of about 400 transistors. It has an open pad of an area of $50{\times}50{\mu}m2$ of CSA(charge Sensitive Amplifier) with x-ray detector through a bump bonding. To reduce layout size, self-biased folded cascode CMOS OP amp is used instead of folded cascode OP amp with voltage bias circuit at each single-pixel CSA, and 15-bit LFSR(Linear Feedback Shift Register) counter clock generator is proposed to remove short pulse which occurs from the clock before and after it enters the counting mode. And it is designed that sensor data can be read out of the sensor column by column using a column address decoder to reduce the maximum current of the CMOS x-ray image sensor in the readout mode.

• Proceedings of the KIPE Conference
• /
• 2011.07a
• /
• pp.179-180
• /
• 2011

This paper focuses on the Current-Voltage concurrent control method devoted to the multiple LED (light-emitting diode) string driver. Isolated DC to DC converter with cascaded chopping switch is proposed for smart lighting system such as light with sensor or back light unit of display, which need to control the current of parallel connected multiple LED stings and regulate DC voltage for micro controller for brightness control. The proposed circuit regulates the current of parallel connected multiple LED strings and additional DC voltage output simultaneously. To verify the performance, experimental results are presented based on the prototype board. 5V, 1A voltage mode electric load and two LED strings with different forward voltages are used for output loads. 23W output power is achieved and measured efficiency is in the range of 85%-87%

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.28A no.9
• /
• pp.721-728
• /
• 1991

In this paper, a magneto-optic modulator has been designed by using single crystal BSO and polycrystal ZnSe as Faraday cells. And practical core-type optical current sensors using pure iron and permalloy have been prepared and experimented. In order to obtain efficient magnetic field detection, LED(NEC OD08358, 0.87 $\mu$m) was used as optical source, PIN-PD(OD-8454)as optical receiver and multi-mode optical fiber (100/140$\mu$m) as transmission line. The characteristics matrix of the optical element was calculated by Stokes parameter, and optic modulation characteristics equations were derived by Muller matrix. Electromagnetic analysis program (FLUX 2D, micro VAX 3600) by finite element method was used to find the magnetic flux density around the core. The measuring error of the output voltage to input current has been masured below 5% in the range of 50A to 1000A. As the temperature was changed from -20$^{\circ}C$ to 60$^{\circ}C$, the maximum measurement error of the optical output has been found to be 0.5% at 60$^{\circ}C$. These experimental results show good temperature and linearity characteristics. The SNR of the overall system was 47dB in case of 600A (250.2 Oe) conductor current and the system has good noise immunity.

• Journal of IKEEE
• /
• v.22 no.3
• /
• pp.842-845
• /
• 2018

In this paper, we propose low-power operational methods for thermal-energy-harvesting sensor circuits. Here, the amount of harvested current has been measured as low as 8uA. However the DC power consumption of the sensor circuit is known to consume much larger than 8uA. Thus, We propose the hardware-based power gating and software-based active/sleep timing control schemes, respectively, for controlling the power consumption of sensor circuit. In the hardware-based power gating scheme, if the ratio of Toff/Ton is larger than 22, the sensor can consume less than 8uA. For the software-based active/sleep control scheme, if the ratio of Tslp/Tact is larger than 3, we can suppress the current consumption below 8uA. The hardware-based and software-based schemes proposed in this paper would be helpful in various applications of energy-harvesting sensor circuits, where the power consumption is limited by an amount of harvested energy.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.14 no.11
• /
• pp.2541-2547
• /
• 2010

In this paper, we propose a design technique which replaces logic transistors of 1.2V with medium-voltage transistors of 3.3V having small off-leakage current in repetitive block circuits where speed is not an issue, to implement a low-power eFuse OTP memory IP in the stand-by state. In addition, we use dual-port eFuse cells reducing operational current dissipation by reducing capacitances parasitic to RWL (Read word-line) and BL (Bit-line) in the read mode. Furthermore, we propose an equivalent circuit for simulating program power injected to an eFuse from a program voltage. The layout size of the designed 512-bit eFuse OTP memory IP with a 90nm CMOS image sensor process is $342{\mu}m{\times}236{\mu}m$. It is confirmed by measurement experiments on 42 samples with a program voltage of 5V that we get a good result having 97.6 percent of program yield. Also, the minimal operational supply voltage is measured well to be 0.9V.

• Journal of Sensor Science and Technology
• /
• v.18 no.2
• /
• pp.128-134
• /
• 2009

Integrated circuit of a new neuron chain with a synapse function for Hodgkin-Huxley model which is a good electrical model about a real biological neuron is implemented in a $0.5{\mu}m$ 1 poly 2 metal CMOS technology. Pulse type neuron chain consist of series connected current controlled single neurons through synapses. For the realization of the single neuron, a pair of voltage mode oscillators using operational transconductance amplifiers and capacitors is used. The synapse block which is a connection element between neurons consist of a voltage-current conversion circuit using current mirror. SPICE simulation results of the proposed circuit show 160 mV amplitude pulse output and propagation of the signal through synapses. Measurements of the fabricated pulse type neuron chip in condition of ${\pm}2.5\;V$ power supply are shown and compared with the simulated results.

• Journal of Sensor Science and Technology
• /
• v.31 no.4
• /
• pp.271-277
• /
• 2022

We analyzed the effects of the interface trap on the output characteristics of an inversion mode n-channel GaN Schottky barrier (SB)-MOSFET based on the N_it distribution using TCAD simulation. As interface trap number density (N_it) increased, the threshold voltage increased while the drain current density decreased. Under N_it=5.0×10¹⁰ cm^-2 condition, the threshold voltage was 3.2 V for V_DS=1 V, and the drain current density reduced to 2.4 mA/mm relative to the non-trap condition. Regardless of the N_it distribution type, there was an increase in the subthreshold swing (SS) following an increase in N_it. Under U-shaped N_it distribution, it was confirmed that the SS varied depending on the gate voltage. The interface fixed charge (Q_f) caused an shift in the threshold voltage and increased the off-state current collectively with the surface trap. In summary, GaN SB-MOSFET can be a building block for high power UV optoelectronic circuit provided the surface state is significantly reduced.

• Journal of Digital Contents Society
• /
• v.16 no.1
• /
• pp.97-104
• /
• 2015

The conventional 1 Hall sensor-type water gauge has some defects that it can not detect counterflow and low-speed flow of water, and it also generates power consumption during even sleep mode. In this paper, a low-power consumption wireless digital remote water gauge with a counterflow detection capability is proposed. The proposed water gauge detects the direction and amount of water flow by using the three Hall sensors placed at $120^{\circ}$ intervals with 8-year national standard life durability. The water gauge with three Hall sensors works without error regardless of water speed does not generate power dissipation during sleep mode by presented reading algorithm for bew water gauge. The proposed water gauge is designed to send its ID, current time and counting value to repeater or central control center with specified frequency by RF Module.

• Smart Structures and Systems
• /
• v.29 no.5
• /
• pp.661-675
• /
• 2022

In this paper, an electric vehicle drives with efficient control and low cost hardware using four quadrant DC converter with Permanent Magnet Direct Current (PMDC) motor fed by DC boost converter is presented. The main idea of this work is to improve the energy efficiency of the conversion chain of an electric vehicle by inserting a boost converter between the battery and the four quadrant-DC motor chopper assembly. Consequently, this method makes it possible to maintain the amplification gain of the 4 quadrant chopper constant regardless of the battery voltage drop and even in the presence of a fault in the battery. One of the most important control problems is control under heavy uncertainty conditions. The higher order sliding mode control technique is introduced for the adjustment of DC bus voltage and mechanical motor speed. To implement the proposed approach in the automotive field, experimental tests were carried out. The performances obtained show the usefulness of this system for a better energy management of an electric vehicle and an ideal control under different operating conditions and constraints, mostly at nominal operation, in the presence of a load torque, when reversing the direction of rotation of the motor speed and even in case of battery chamber failure. The whole system has been tested experimentally and its performance has been analyzed.

• Journal of Korea Multimedia Society
• /
• v.21 no.6
• /
• pp.649-658
• /
• 2018

In this paper, we propose a mechanical contact inner tap inspection system that can inspect the defect of the inner tap immediately after inner tap is processed within the machining center. The inspection module has the collet chuck structure, so it can mounted on the main spindle of the machining center during inspection. It was developed with a focus on inspection for tap having 20 mm depth which is primarily fabricated in automotive parts and has a double sided PCB-type control system including sensing function based on Zigbee module, micom and IR sensor for wireless transmission of measured data with low power operation, and also a battery for supplying electric power. The current consumption is 46.8mA in the inspection operation mode and 0.0268mA in the power saving mode for 3.7V of the applied power source, so that 30,000 times or more inspection can be performed with assumed 5 seconds inspection time for one tap. Experiments in test jig system and actual machining center confirm that the proposed inner tap inspection system can be applied to the batch process of simultaneous inspection after tapping in the machining center.