• Journal of Sensor Science and Technology
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• v.25 no.5
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• pp.349-353
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• 2016

Recently, research on bolometer-type uncooled infrared image sensor which is made for industrial applications has been increasing. In general, it is difficult to calibrate fixed pattern noise (FPN) of bolometer array. In this paper, average-current calibration algorithm is presented for reducing bolometer resistance offset. A resistor which is produced by standard CMOS process, on the average, has a deviation. We compensate for deviation of each resistor using average-current calibration algorithm. The proposed algorithm has been implemented by a chip which is consisted of a bolometer pixel array, average current generators, current-to-voltage converters (IVCs), a digital-to-analog converter (DAC), and analog-to-digital converters (ADCs). These bolometer-resistor array and readout circuit were designed and manufactured by $0.35{\mu}m$ standard CMOS process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.347-348
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• 2007

On-chip micro humidity sensor, using $CN_x$ films for the sensing material, was designed, simulated, and fabricated with Op amp based readout circuit and diode temperature sensors. To compensate the temperature and other gases, two methods were applied. One is wheatstone-bridge with reference FET that eliminates other undesirable chemical species, and the other is a diode temperature sensor to compensate the temperature effect. $CN_x$ film can be a new humidity sensing material, and has a strong potential to adapt to smart sensors or multi-sensors using MEMS or nano-technology. A particular design technology for integration of sensors and systems together was proposed that whole fabrication process could be achieved by a standard CMOS process.

• Smart Structures and Systems
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• v.9 no.6
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• pp.535-547
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• 2012

Controlling the balance of motion in a context involving a biped robot navigating a rugged surface or a step is a difficult task. In the present study, a $3{\times}5$ flexible piezoelectric tactile sensor array is developed to provide a foot pressure map and zero moment point for a biped robot. We introduce an innovative concept involving structural electrodes on a piezoelectric film in order to improve the sensitivity. The tactile sensor consists of a polymer piezoelectric film, PVDF, between two patterned flexible print circuit substrates (FPC). Additionally, a silicon rubber bump-like structure is attached to the FPC and covered by a polydimethylsiloxane (PDMS) layer. Experimental results show that the output signal of the sensor exhibits a linear behavior within 0.2 N ~ 9 N, while its sensitivity is approximately 42 mV/N. According to the characteristic of the tactile sensor, the readout module is designed for an in-situ display of the pressure magnitudes and distribution within $3{\times}5$ taxels. Furthermore, the trajectory of the zero moment point (ZMP) can also be calculated by this program. Consequently, our tactile sensor module can provide the pressure map and ZMP information to the in-situ feedback to control the balance of moment for a biped robot.

• Journal of Astronomy and Space Sciences
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• v.24 no.4
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• pp.349-366
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• 2007

We designed and developed a multi-purpose CCD camera system for three kinds of CCDs; KAF-0401E($768{\times}512$), KAF-1602E($1536{\times}1024$), KAF-3200E($2184{\times}1472$) made by KODAK Co.. The system supports fast USB port as well as parallel port for data I/O and control signal. The packing is based on two stage circuit boards for size reduction and contains built-in filter wheel. Basic hardware components include clock pattern circuit, A/D conversion circuit, CCD data flow control circuit, and CCD temperature control unit. The CCD temperature can be controlled with accuracy of approximately $0.4^{\circ}C$ in the max. range of temperature, ${\Delta}33^{\circ}C$. This CCD camera system has with readout noise $6\;e^-$, and system gain $5\;e^-/ADU$. A total of 10 CCD camera systems were produced and our tests show that all of them show passable performance.

• Publications of The Korean Astronomical Society
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• v.21 no.2
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• pp.67-74
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• 2006

We have developed a control electronics system for an infrared detector array of KASINICS (KASI Near Infrared Camera System), which is a new ground-based instrument of the Korea Astronomy and Space science Institute (KASI). Equipped with a $512{\times}512$ InSb array (ALADDIN III Quadrant, manufactured by Raytheon) sensitive from 1 to $5{\mu}m$, KASINICS will be used at J, H, Ks, and L-bands. The controller consists of DSP(Digital Signal Processor), Bias, Clock, and Video boards which are installed on a single VME-bus backplane. TMS320C6713DSP, FPGA(Field Programmable Gate Array), and 384-MB SDRAM(Synchronous Dynamic Random Access Memory) are included in the DSP board. DSP board manages entire electronics system, generates digital clock patterns and communicates with a PC using USB 2.0 interface. The clock patterns are downloaded from a PC and stored on the FPGA. UART is used for the communication with peripherals. Video board has 4 channel ADC which converts video signal into 16-bit digital numbers. Two video boards are installed on the controller for ALADDIN array. The Bias board provides 16 dc bias voltages and the Clock board has 15 clock channels. We have also coded a DSP firmware and a test version of control software in C-language. The controller is flexible enough to operate a wide range of IR array and CCD. Operational tests of the controller have been successfully finished using a test ROIC (Read-Out Integrated Circuit).

• Journal of Radiation Industry
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• v.6 no.1
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• pp.31-40
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• 2012

There are two methods to fabricate the readout electronic to a large-area CMOS image sensor (LACIS). One is to design and manufacture the sensor part and signal processing electronics in a single chip and the other is to integrate both parts with bump bonding or wire bonding after manufacturing both parts separately. The latter method has an advantage of the high yield because the optimized and specialized fabrication process can be chosen in designing and manufacturing each part. In this paper, LACIS chip, that is optimized design for the latter method of fabrication, is presented. The LACIS chip consists of a 3-TR pixel photodiode array, row driver (or called as a gate driver) circuit, and bonding pads to the external readout ICs. Among 4 types of the photodiode structure available in a standard CMOS process, $N_{photo}/P_{epi}$ type photodiode showed the highest quantum efficiency in the simulation study, though it requires one additional mask to control the doping concentration of $N_{photo}$ layer. The optimized channel widths and lengths of 3 pixel transistors are also determined by simulation. The select transistor is not significantly affected by channel length and width. But source follower transistor is strongly influenced by length and width. In row driver, to reduce signal time delay by high capacitance at output node, three stage inverter drivers are used. And channel width of the inverter driver increases gradually in each step. The sensor has very long metal wire that is about 170 mm. The repeater consisted of inverters is applied proper amount of pixel rows. It can help to reduce the long metal-line delay.

• Journal of Sensor Science and Technology
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• v.18 no.1
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• pp.77-85
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• 2009

We propose a new image pixel architecture which has OFD(Over Flow Device) node by improving conventional 3TR pixel structure. Newly designed pixel consists of photo diode which is verified with HSPICE simulation, PMOS reset transistor, several NMOS and several PMOS transistors. Photodiode signals from each PMOS and NMOS are detected by Reset PMOS. These output signals give enough chances to detect wide operation coverage because OFD node has overflow photocurrent. According to various light intensity, we analyzed characteristic of the output voltage with a SPICE tool. Proposed pixel output has specific value which can detect possible from $0.1{\mu}W/cm^2$ to $10W/cm^2$ light intensity. It has wide-dynamic range of 160 dB.

• 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.

• Journal of Sensor Science and Technology
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• v.27 no.6
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• pp.397-402
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• 2018

Proper seat design is critical to the safety, comfort, and ergonomics of automotive driver's seats. To ensure effective seat design, quantitative methods should be used to evaluate the characteristics of automotive seats. This paper presents a system that is capable of simultaneously monitoring body pressure distribution and surface deformation in a textile material. In this study, a textile-based capacitive sensor was used to detect the body pressure distribution in an automotive seat. In addition, a strain gauge sensor was used to detect the degree of curvature deformation due to high-pressure points. The textile-based capacitive sensor was fabricated from the conductive fabric and a polyurethane insulator with a high signal-to-noise ratio. The strain gauge sensor was attached on the guiding film to maximize the effect of its deformation due to bending. Ten pressure sensors were placed symmetrically in the hip area and six strain gauge sensors were distributed on both sides of the seat cushion. A readout circuit monitored the absolute and relative values from the sensors in realtime, and the results were displayed as a color map. Moreover, we verified the proposed system for quantifying the body pressure and fabric deformation by studying 18 participants who performed three predefined postures. The proposed system showed desirable results and is expected to improve seat safety and comfort when applied to the design of various seat types. Moreover, the proposed system will provide analytical criteria in the design and durability testing of automotive seats.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.10
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• pp.2359-2368
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• 2013

In this paper, an IRD (internal read data) circuit preventing the reentry into the read mode while keeping the read-out DOUT datum at power-up even if noise such as glitches occurs at signal ports such as an input signal port RD (read) when a power IC is on, is proposed. Also, a pulsed WL (word line) driving method is used to prevent a DC current of several tens of micro amperes from flowing into the read transistor of a differential paired eFuse OTP cell. Thus, reliability is secured by preventing non-blown eFuse links from being blown by the EM (electro-migration). Furthermore, a compared output between a programmed datum and a read-out datum is outputted to the PFb (pass fail bar) pin while performing a sensing margin test with a variable pull-up load in consideration of resistance variation of a programmed eFuse in the program-verify-read mode. The layout size of the 8-bit eFuse OTP IP with a $0.18{\mu}m$ process is $189.625{\mu}m{\times}138.850{\mu}m(=0.0263mm^2)$.