• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.6
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• pp.728-735
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• 2016

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.

• Journal of Ocean Engineering and Technology
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• v.26 no.1
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• pp.27-33
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• 2012

This paper presents the effect of temperature on the impedance-based damage monitoring of steel-bolt connections using wireless impedance sensor nodes. In order to achieve the objective, the following approaches are implemented. First, a temperature-compensated damage monitoring scheme that includes a temperature compensation model and damage detection method is described. The temperature compensation model is designed by analyzing the linear regressions between the temperatures and impedance signatures. The correlation coefficient of the impedance signatures is selected as the damage index to monitor the damage occurrence in the target structures. Second, a wireless impedance sensor node is described for the design of the hardware components and embedded software. Finally, the performance of the temperature-compensated impedance-based damage monitoring scheme is evaluated for detecting a loose bolt in the steel-bolt connections on a lab-scale steel girder under various temperatures.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.593-594
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• 2008

In this article, process voltage temperature (PVT) compensated on-chip oscillator is implemented by using proportional to absolute temperature (PTAT) circuit and process compensator. Process compensator circuit based on current subtracter and PTAT circuit are proposed for compensation of oscillation frequency to cope with process variation and temperature variation. All circuit can operate in the range of $3.5{\sim}5\;V$ supply voltage. It can be applied to PVT insensitive low frequency clock reference generator.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.612-614
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• 2000

We propose a new curvature-compensated CMOS bandgap reference circuit that is achieved by varying a current ratio. The proposed circuit is shown to have small temperature coefficient that the output voltage variation is 0.4mV.

• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.3
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• pp.105-113
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• 2007

This study was conducted to analyze the effects of environmental factors such as soil moisture, light intensity, temperature and humidity on changes in cambial electrical resistance. To improve data quality, cambial electrical resistance was continuously measured at fixed points by using a data logger isolated from alternating current. The relationship between environmental factors and changes in cambial electrical resistance was also analyzed. The results are as follows: 1. Cambial electrical resistance is highly correlated to the temperature of the measured area(r=-0.934). Therefore, temperature compensation is needed to analyze the effects of other environmental factors on cambial electrical resistance changes. 2. If temperature is compensated for, the change of cambial electrical resistance is highly correlated to water vapor pressure(r=-0.836). 3. If temperature and humidity are compensated for, the change of cambial electrical resistance is highly correlated to intensity of light(r=-0.738). 4. Diurnal deviation of soil water potential is not more significantly related than the change of cambial electrical resistance. However, in the long-term, soil water potential and cambial electrical resistance are highly correlated(r=-0.831). This indicates that soil moisture significantly influences the long-term change of cambial electrical resistance.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.7
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• pp.610-614
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• 2005

In this paper, simple AT-cut crystal resonator utilizing $Bi_{0.5}(Na_{0.84}K_{0.16})_{0.5}TiO_3$ relaxator ceramics as load capacitator were designed and their frequency-temperature characteristics were investigated. In order to modify temperature dependance of dielectric constant, $Bi_{0.5}(Na_{0.84}K_{0.16})_{0.5}TiO_3$ ceramics were manufactured with the variations in Sr substitution. At the composition with $6\;mol\%$ Sr substitution as load capacitator, frequency-temperature characteristics of AT-cut crystal resonators with the series load capacitance were similarly varied as those of cut orientation variation, and also compensated.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.43 no.6 s.312
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• pp.27-32
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• 2006

A temperature-compensated hygrometer has been developed using resistive humidity sensors. It consist of a sine wave generator, logarithm converters, rectifiers, and amplifiers. The hygrometer accomplishes the linearization and temperature compensation of sensor characteristics. The theory of operation is presented and experimental results are used to verify theoretical predictions. The experimental results show that the conversion sensitivity of the hygrometer is about 24.8 mV/%RH and the linearity error of the conversion characteristic is less than 17.2 % over a relative humidity range from 30 to 80 %RH. The results also show that the temperature coefficient of the output voltage is less than $10149ppm/^{\circ}C$ over a temperature range from 22 to $40^{\circ}C$.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.1
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• pp.61-70
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• 2004

In this paper, we propose the color-temperature conversion system with compensated X-chromaticity coordinate. It uses a linear regression to improve the error of color-temperatue calculation in conventional systems. It also extend the color-temperature range from 1,667K to 25,000K to Provide a wider color-temperature range. We show the effectiveness of the proposed method by comparing the performance of the proposed method with those of the Robertson's and the existing methods. The proposed method is experimetally verified by displaying the results on a TV system through the Xilinx FPGA XCV2000E-BG560.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.4C
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• pp.117-125
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• 2011

The practical use of the electrical resistivity, which can makes the acquirement of the high resolution data in specific area, is increased in order to obtain a reasonable data for a ground investigation. The objective of this study is development of TRPF(Temperature-compensated Resistivity Probe for Field test), and an application in the field test for obtaining a reliable electrical resistivity value about considering the temperature effects. Temperature sensor is attached at 15mm, 30mm, 90mm below from the cone tip in consideration with the results of temperature transient process of cone probe and safety, and the angle of cone tip is $60^{\circ}$ for geometrical reason and minimizing the disturbance during the penetration test. Diameter of the cone probe is equally 35.7mm and penetration rate is 2 cm/sec for a comparison with standard cones such as CPT and SPT, and others. The temperature change is instantly observed around $4^{\circ}C$ when touching the ground, and the comparing results among the other cones indicates that the temperature compensation should be conducted in the ground survey using the electrical resistivity. This study shows that the necessity of temperature effects compensation during penetration test through the development and field verification of TRPF (Temperature-compensated Resistivity Probe for Field test).

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2365-2367
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• 2000

The deterministic errors of semiconductor gyros and accelerometers must be estimated and compensated to develop the low-cost IMU using them. Generally, the dominant errors of the low-cost IMU are bias and misalignment errors. Bias is sensitive to temperature. Therefore, in this paper, the effect on temperature of bias is analyzed and temperature compensation are carryed out. It is shown by experiment that the compensation is efficient.