• 한국ITS학회 논문지
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• 제11권4호
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• pp.63-69
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• 2012

본 논문에서는 용량성 지문센서의 회색조 이미지를 얻기 위한 새로운 회로를 제안하고 있다. 기존의 회로는 회색조 이미지를 얻기 위해 많은 칩 면적을 차지하는 DAC를 적용하거나 전력소모가 많고 전역 클럭을 적용하는 비휘발성 메모리에 적용되는 승압회로를 픽셀별로 적용하였다. 개선된 전하분할 방식의 용량성 지문센서 감지회로는 뉴런모스(vMOS) 기반의 DLC(down literal circuit) 회로와 단순화된 아날로그 MUX(multiplexor)를 적용하였다. 설계된 감지회로는 0.3V, $0.35{\mu}m$ CMOS공정을 적용하여 동작을 검증하였다. 제안된 회로는 기존의 비교기와 주변회로를 필요로하지 않으므로 단위 픽셀의 레이아웃 면적을 줄이고 이미지의 해상도를 향상 시킬 수 있다.

• Journal of information and communication convergence engineering
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• 제10권2호
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• pp.194-199
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• 2012

This paper proposes a novel scheme of a gray scale fingerprint image for a high-accuracy capacitive sensor chip. The conventional grayscale image scheme uses a digital-to-analog converter (DAC) of a large-scale layout or charge-pump circuit with high power consumption and complexity by a global clock signal. A modified capacitive detection circuit for the charge sharing scheme is proposed, which uses a down literal circuit (DLC) with a floating-gate metal-oxide semiconductor transistor (FGMOS) based on a neuron model. The detection circuit is designed and simulated in a 3.3 V, 0.35 ${\mu}m$ standard CMOS process. Because the proposed circuit does not need a comparator and peripheral circuits, the pixel layout size can be reduced and the image resolution can be improved.

• 센서학회지
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• 제14권1호
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• pp.28-32
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• 2005

In this paper, a CMOS integrated detection circuit for capacitive type fingerprint sensor signal processing is described. We designed a detection circuit of charge-sharing sensing scheme. The proposed detection circuit increases the voltage difference between a ridge and valley. The test chip is composed of $160{\times}192$ array sensing cells (12 by $12.7{\;}mm^{2}$). The chip was fabricated on a 0.35 m standard CMOS process. Measured difference voltage between a ridge and valley was 0.95 V.

• Journal of information and communication convergence engineering
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• 제9권3호
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• pp.301-304
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• 2011

This paper describes the possibility of a low-power, high-resolution fingerprint sensor chip. A modified capacitive detection circuit of charge sharing scheme is proposed, which reduces the static power dissipation and increases the voltage difference between a ridge and valley more than conventional circuit. The detection circuit is designed and simulated in 3.3V, 0.35${\mu}$m standard CMOS process, 40MHz condition. The result shows about 27% power dissipation reduction and 90% improvement of difference between a ridge and valley sensing voltage. The proposed circuit is more stable and effective than a typical circuit.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 춘계학술대회
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• pp.692-695
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• 2011

This paper describes the possibility of a low-power, high-resolution fingerprint sensor chip. A modified capacitive detection circuit of charge sharing scheme is proposed, which reduces the static power dissipation and increases the voltage difference between a ridge and valley more than conventional circuit. The detection circuit is designed and simulated in 3.3V, $0.35{\mu}m$ standard CMOS process, 40MHz condition. The result shows about 35% power dissipation reduction and 90% improvement of difference between a ridge and valley sensing voltage. The proposed circuit is more stable and effective than a typical circuit.

• 한국전기전자재료학회논문지
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• 제22권9호
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• pp.786-791
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• 2009

Transformer failures are mostly due to partial discharges (PDs) caused by the deteriorated insulation. It is, therefore, important to monitor PD occurrence in insulation system and prevent their deterioration. The presented paper deals with a PD detection method by a capacitive probe, which easily apply to cast - resin dry - type transformers. The PD detection system consists of a capacitive probe and a low noise amplifier having the frequency bandwidth of 500 $Hz{\sim}30$ MHz. In the experimental set-up, sensitivity of the system is 7.16 mV/pC.

• 대한의용생체공학회:의공학회지
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• 제35권4호
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• pp.87-94
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• 2014

Recent technological advances have increased interest in personal health monitoring. Electrocardiogram(ECG) monitoring is a basic healthcare activity and can provide decisive information regarding cardiovascular system status. In this study, we developed a capacitive ECG measurement system that can be included within a cloth mattress pad. The device permits ECG data to be obtained during sleep by using capacitive electrodes. However, it is difficult to detect R-wave peaks automatically because signals obtained from the system can include a high level of noise from various sources. Because R-peak detection is important in ECG applications, we developed an algorithm that can reduce noise and improve detection accuracy under noisy conditions. Algorithm reliability was evaluated by determining its sensitivity(Se), positive predictivity(+P), and error rate(Er) by using data from the MIT-BIH Polysomnographic Database and from our capacitive ECG system. The results showed that Se = 99.75%, +P = 99.77%, and Er = 0.47% for MIT-BIH Polysomnographic Database while Se = 96.47%, +P = 99.32%, and Er = 4.34% for our capacitive ECG system. Based on those results, we conclude that our R-peak detection method is capable of providing useful ECG information, even under noisy signal conditions.

• 한국정보통신학회논문지
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• 제15권6호
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• pp.1343-1348
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• 2011

본 논문에서는 개선된 회로를 적용한 용량성 센서용 저전력 전하분할 방식의 지문센서 감지회로를 제안하고 있다. 제안된 회로는 기존회로에 비하여 전력소모를 크게 줄이고 융선과 골간의 감지전압차를 확대하였다. 설계된 회로는 40MHz 동작주파수, 3.3V 전원에 $0.35{\mu}m$ 표준 CMOS 공정 파라미터를 적용하여 시뮬레이션을 실시하였다. 검증결과 47% 전력소모 감소를 보였고 융선과 골간의 감지 전압 차에 있어서 90% 증가를 나타내었다. 제안된 회로는 면적의 증가 없이 기존 픽셀 레이아웃에 구현되었다.

• 한국전기전자재료학회논문지
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• 제24권4호
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• pp.319-324
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• 2011

This paper dealt with a partial discharge (PD) detection method for insulation diagnosis in cast-resin transformers. To detect PD pulse, a planar-capacitive probe was designed and fabricated. The probe has no insulation problem and can be installed on cast-resin transformers even in operation since it does not connect with high voltage conductor. The PD measurement system consists of the capacitive probe, a coupling network of 100 [kHz] low-cutoff frequency, and an amplifier with a gain of 40 [dB] and a frequency bandwidth of 500 [Hz]~45 [MHz]. A plane-needle and a plane-plane electrode system were fabricated to simulate insulation defects in a cast-resin transformer. Sensitivity of the PD measurement system, which is evaluated by a standard calibrator was 0.35 [mV/pC] for positive and 0.45 [mV/pC] for negative, respectively. The PD detection by the capacitive probe was less sensitive than that by a coupling capacitor according to IEC 60270, but we could analyze the magnitude and the phase distribution of PD pulse.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.900-903
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• 2002

Partial discharges(PD) in air, corona discharges, deteriorate the insulation strength. So, it is necessary to detect PD at an early stage before the system failure and extensive damage to the equipment. PD emit signals which can be detected by applying an capacitive electric field diagnosis. In this paper, We measured signals by capacitive electric field sensor and analyzed FFT from PD, and then compared conventional electric PD detecting method to capacitive electric field diagnosis by $\Psi-q-n$, $\Psi-v-n$, $\Psi-n$, $\Psi-q$ distributions.