• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.8
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• pp.79-85
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• 2009

In this paper, an accurate current reference using temperature and process compensation current mirror (TPC-CM) is proposed. The temperature independent reference current is generated by summing a proportional to absolute temperature (PTAT) current and a complementary to absolute temperature (CTAT) current. However, the temperature coefficient and magnitude of the reference current are influenced by the process variation. To calibrate the process variation, the proposed TPC-CM uses two binary weighted current mirrors which control the temperature coefficient and magnitude of the reference current. After the PTAT and CTAT current is measured, the switch codes of the TPC-CM is fixed in order that the magnitude of reference current is independent to temperature. And, the codes are stored in the non-volatile memory. In the simulation, the effect of the process variation is reduced to 0.52% from 19.7% after the calibration using a TPC-CM in chip-by-chip. A current reference chip is fabricated with a 3.3V 0.35um CMOS process. The measured calibrated reference current has 0.42% variation for $20^{\circ}$C${\sim}$100$^{\circ}$C.

• Journal of the Institute of Convergence Signal Processing
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• v.7 no.4
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• pp.195-200
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• 2006

The conventional discrete circuit for ABS/TCS system was examined and the problems of the system were analyzed by computer simulation. In order to improve the performance of ABS/TCS system, interface IC which has error compensation, comparator and under voltage lock-out circuit was designed and their electrical characteristics were investigated. The voltage regulator was included to compensate the temperature variation in the temperature range from $-20^{\circ}C$ to $120^{\circ}C$ for automobile environment. ABS and brake signal were separated using the duty factor of same frequency or different frequencies. UVLO(Under Voltage Lock-Out) circuit and constant current circuit were applied for the elimination of noise, and protection circuit was applied to cut the excess current off. Layout for IC fabrication was designed to enhance the electrical performance of ABS/TCS system. Layout was consisted of 11 masks, arrayed effectively 8 pads to reduce the current loss. We can see that the result of layout simulation was better than the result of bread board.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.144-145
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• 2012

최근 주목을 받고 있는 온라인 전기자동차의 픽업회로에서 외부온도 변화에 따라 주파수가 변동한다. 이러한 변동에 따라서 전달효율이 저하되는 문제점이 발생한다. 따라서 본 논문에서는 온라인 전기자동차의 픽업회로에서의 주파수 변동을 분석하고 이에 적합한 보상회로를 제안한다.

• Journal of KIISE:Information Networking
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• v.37 no.5
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• pp.403-408
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• 2010

The sensor nodes can be installed in the environment in which the temperature change is considerable, such as desert, urban, and data center. Particularly, because the output power becomes less than the targeted power if a temperature is increasing, link quality is degraded and packet losses are occurred. In order to compensate the temperature changes, existing schemes detect the change of the link quality between nodes and control transmission power through a series of feedback process. However, these approaches can cause heavy overhead by additional control packets. In this paper, we propose the T2PC(Temperature-aware Transmission Power Control) to keep up the link quality despite temperature variation. At each node, T2PC compensates the attenuated link quality by controlling the transmission power based on the local temperature measurement. In addition, the packet reception ratio can be improved with less control packets than ones required in existing transmission power control methods based on the feedback control.

• The Journal of Korean Society for Radiation Therapy
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• v.29 no.2
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• pp.27-32
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• 2017

Objectives: Oncological hyperthermia is a treatment to selectively kill cancer cells by directly applying heat to cancer cells or indirectly demage cancer cells. One of the most side effects of treatment is burn that can appear on the skin. In areas with irregularities such as the umbilicus, the patient feels a sense of hot and treatment may be discontinued. Therefore, in order to eliminate the irregularities of these areas, compensators are manufactured and measured to decrease in temperature. Materials and Methods: The temperature of the four sites (umbilicus, near the umbilicus, 5 cm below the umbilicus, back) was measured five times around the umbilicus in patients who were treated at oncological hyperthermia treatment device(EHY-2000, Oncotherm Kft, Hungary). The temperature sensor (TM-100, Oncotherm Kft, Hungary) was attached to four sites and the changes were observed at 5, 15, 25, 35, and 50 minutes after treatment. Compensators of three materials were used(Vaseline, Bolus, Dental resin). The data measured five times were compared for each compensator. Results: The temperature change when the compensator was not used increase from 34.65 degrees to 42.9 degrees on average. The near umbilicus was changed from 32.20 degrees to 37.00 degrees, and the 5 cm below the umbilicus was changed from 31.90 to 34.41 degrees. When the compensator material was inserted into the umbilicus, the temperature change was measured as 5.42 degrees for bolus, 6.55 degrees for vaseline, and 6.83 degrees for resin. Conclusion: Using the compensator in the region where the irregularities such as the umbilicus, the heat sensation could be reduced. the use of a resin that can be customized not only lowers the temperature but also significantly reduces the feeling of the patient. It will be possible to reduce the heat sensation in the treatment and to treat it in a more comfortable condition.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.6
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• pp.514-520
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• 2002

In this paper, the study of a design and fabrication of the receiver MMIC mixer for L-band application is described. The mixer is composed of active LO and RF balun to integrate on a chip and applied a newly proposed bias circuit to compensate the process variations of active devices. The conversion gain of the mixer is -14 dB, IIP3 is approximately 4 dBm and port-to-port isolation is over 25 dB. The newly proposed bias circuit is composed of a few FETs and resistors, and can compensate the variation of the threshold voltage by the process variations, temperature changes and etc. The designed chip size is $1.4\;mm{\times}1.4\;mm$.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.43 no.5 s.311
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• pp.28-35
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• 2006

This paper presents a new 3.3-1 V synchronous buck DC/DC converter that employs CMOS operational transconductance amplifiers (OTAs) as circuit-building blocks. An error amplifier OTA in a PWM circuit is compensated for to improve temperature stability. The temperature coefficient of the transconductance gain of the compensated OTA is less than $150\;ppm/^{\circ}C\;over\;0-100^{\circ}C$. The HSPICE simulation results of the $0.3{\mu}m$ standard CMOS technology show that the efficiency of the proposed converter is as high as 80% in the load current range of 40-125 mA. These results show that the proposed converter is adequate for use in battery-operated systems.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.9
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• pp.798-805
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• 2015

This paper proposes Relaxation Oscillator with Random Number Generator to minimize electromagnetic interference (EMI) noise. DC-DC Converter with Relaxation Oscillator is presented how much spurious noise effects to RF Receiver system. The main frequency of the proposed Relaxation oscillator is 7.9 MHz to operate it and add temperature compensation block to be applied to the frequency compensation in response to temperature changes. The DC-DC Converter Spurious noise is reduced up to 20 dB through changing frequency randomly. It is fabricated in $0.18{\mu}m$ CMOS technology. The active area occupies an area of $220{\mu}m{\times}280{\mu}m$. The supply voltage is 1.8 V and current consumption is $500{\mu}A$.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.6
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• pp.584-591
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• 2004

The conventional analog-based firing circuit can be implemented by comparing a linearly decreasing periodic sawtooth waveform synchronized to the ac supply, with a control signal corresponding to the desired converter delay angle. This circuit requires a large number of passive components (resistance and capacitor) and careful adjustment of the synchronization circuity. In this paper a novel firing circuit is proposed for thyristor switch. The proposed circuit is implemented by using digital components(FPGA, A/D, and DSP etc.) on the basis of the analog cosine method.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.4
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• pp.78-83
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• 1996

A timing recovery circuit of 10 Gbit/s optical receiver is described. The circuit consists of a passive NRZ-to-PRZ circuit, a dielectric resonator filter (DRF) and a narrow band amplifier, which for the first time adopted a temperature compensation technique using the tempareature characteristics of DR. The experimental results showed an output clock phase variation of less than ${\pm}$6 degree over the operating temperature range form 0$^{\circ}C$ to 75$^{\circ}C$ and measured maximum rms jitters of less than 2 phs with the resonance detunings of up to ${\pm}$10 MHz. These experimental results show that the circuit is a suitable for 10 Gbit/s lightwave transmission system.