• 센서학회지
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• 제26권5호
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• pp.331-337
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• 2017

A readout circuit for a tactile sensor pad based on force sensing resistors was proposed, which was composed of an analog signal conditioning circuit and a digital circuit with a microcontroller. The conventional signal conditioning circuit has a dc offset voltage in the output signal, which results from the reference voltage applied to the FSR devices. The offset voltage reduces the dynamic range of the circuit and makes it difficult to operate the circuit under a low voltage power supply. In the proposed signal conditioning circuit, the dc offset voltage was removed completely. The microcontroller with A/D converter and D/A converter was used to enlarge the measurement range of pressure. For this, the microcontroller adjusts the FSR reference voltage according to the resistance magnitude of FSR under pressure. The operation of the proposed readout circuit which was connected to a tactile sensor pad with $5{\times}10$ FSR array was verified experimentally. The experimental results show the proposed readout circuit has the wider measurement range of pressure than the conventional circuit. The proposed circuit is suitable for low voltage and low power applications.

• 센서학회지
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• 제19권3호
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• pp.230-237
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• 2010

In sensor signal conditioning and processing, offset and drift characteristics of an operational amplifier are an important factor when the amplifier is used for a precise sensor signal amplifier. In order to use it in high accuracy, an expensive trimming or a complex compensation circuit is required. This paper presents the improved sensor signal conditioning and processing device for ubiquitous sensor network(USN) application or general purpose by developing a hardware of the circuit for reducing the offset voltage and drift characteristics, and a software for its control and sensor signal processing. We realize better offset voltage and drift characteristics of the signal conditioning circuit using low cost operational amplifiers. The experimental results show that this technique is effective in improving the performance of the sensor signal processing device.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.31-32
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• 2006

A signal conditioning circuit for capacitive sensors was developed using a commercial single chip solution. Since capacitive displacement sensors can achieve high resolution and linearity, they have been widely used as precision sensors within the range of several hundred micrometers. However, they inherently have a limitation in low frequency range and some nonlinearity characteristics and so a specially designed signal conditioning circuit is needed to handle these properties. Up to now, several companies already have succeeded in the development of the capacitive sensors system and they are commercially available in the market. In this research, to construct the signal processing circuits more easily and simply, we used a universal LVDT signal conditioner (AD698). Since the AD698 provides one chip solution for a basic signal processing including modulation and demodulation using various internal components, we can build the processing circuits successfully with minimal additional circuits: a compensation circuits for the drift caused by the bias current of OP amplifiers and a fine adjustment circuit for the elimination of nonlinearity. The signal processing circuits shows nonlinearity less than 0.05% in the comparison with a laser interferometer.

• 한국정밀공학회지
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• 제24권9호
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• pp.60-67
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• 2007

A signal conditioning circuit for capacitive displacement sensors was developed using a high frequency modulation/demodulation method, and its performance was evaluated. Since capacitive displacement sensors can achieve high resolution and linearity, they have been widely used as precision sensors within the range of several hundred micrometers. However, they inherently have a limitation in low frequency range and some nonlinearity characteristics and so a specially designed signal conditioning circuit is needed to handle these properties. The developed signal processing circuit consists of three parts: linearization, modulation/demodulation, and nonlinearity compensation. Each part was constructed discretely using several IC chips and passive elements. An evaluation system for precision displacement sensors was developed using a laser interferometer, a precision stage, and a PID position controller. The signal processing circuit was tested using the evaluation system in the respect of resolution, repeatability, linearity, and so on. From the experimental results, we know that a highly linear voltage output can be obtained successfully, which is proportional to displacement and the nonlinearity of output is less than 0.02% of full range. However, in the future, further investigation is required to reduce noise level and phase delay due to a low-pass filter. The evaluation system also can be applied effectively to calibration and evaluation of precision sensors and stages.

• 센서학회지
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• 제5권6호
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• pp.25-34
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• 1996

본 논문에서는 압저항형 압력센서를 위한 신호처리회로를 설계하였다. 신호처리회로는 압저항형 압력센서를 구동하기 위한 기준전압 회로와 미소한 센서 신호의 증폭을 위한 인스트루먼트 증폭기로 구성이 되어있다. 신호처리회로는 단일 폴리 이중 메탈(single poly double metal) $1.5\;{\mu}m$ BiCMOS 공정 파라미터를 이용하여 HSPICE로 시뮬레이션 하였다. 시뮬레이션 결과, 밴드갭 기준전압회로의 온도 계수는 $0\;{\sim}\;70^{\circ}C$의 범위에서 $21\;ppm/^{\circ}C$였고 PSRR은 80 dB였다. BiCMOS 증폭기의 이득, 옵셋, CMRR, CMR, PSRR, 특성은 CMOS나 바이폴라보다 우수하였고 전력소비 및 잡음전압 특성은 CMOS가 우수하였다. 설계한 신호처리 회로는 옵셋이 적고 입력 임피던스가 높으며 CMRR 특성이 우수하기 때문에 센서 및 계측용 신호처리회로로서 사용하기에 적합하다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.581-584
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• 2003

The phase differences and noise signals are in general serious on output of a instrumentation amplifier for signal conditioning of a sensor driven at high frequency due to a time-varying input signal. In this study, we get the better amplification and S/N ratio using the rectified signal for the input of instrumentation amplifier. This driving circuits were designed and constructed by OrCAD and laboratory PCB process. All of the elements used on the circuit including highly speedy OP-Amp. was SMD type and the MI sensor was fabricated by meander-patterned amorphous ribbon. The output sensitivity of this circuit was $105.3mV/V{\cdot}Oe$. That's why this driving circuit is good at detection of fine magnetic field.

• 대한전기학회논문지:시스템및제어부문D
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• 제50권11호
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• pp.550-556
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• 2001

The computerized cardiac analysis system, which acquires and analyzes the electrical activation signal propagating along the surface of the heart, is indispensible equipment for the open heart surgery and electrical cardiac study. In this paper, the design requirement and the electrical circuit analysis are performed to construct the multi-channel cardiac activation pre-amplifier necessary for a signal conditioning circuit. The general 64 channel configuration is expanded into 128 channels to enhance the spatial resolution on the mapped surface of the heart. The 128 channels pre-amplifier consists of input circuit, differential amplifier, right leg driven circuit and isolation part. It has distinct features; high voltage protection, leakage current limitation, isolation and the maximization of common mode rejection ratio with respect to the half-cell potential difference due to different electrode materials. The final pre-amplifier circuit is assembled with 8 boards, each of which composing of 16 channels.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.368-371
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• 1996

This paper describes a study on the developments of the high power brushless DC(BLDC) servo system for electric gun/turret drive system. The servo control unit including the DSP based digital servo unit, power amplifier, signal conditioning circuit, internal power circuit is designed and implemented for driving the 10hp BLDC servo system. The developed system is applied to the gun/turret drive & stabilization simulator system and the control performance is verfied through the experiments.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.532-535
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• 2000

We have fabricated a sensor system for on-line monitoring the oxygen permeability and diffusivity of six different polymer films using the miniaturized 6 cathode(Ag)-single anode(Ag/AgCl) type hexagonal oxygen electrode. This system consists of multiple input front-end electronics, signal conditioning circuit using the embedded microcontroller 80C196KC, PC interface circuit and PC with the OS for microcontroller and the operating program for this system. The digital low-[ass filter was programmed and the simulated filter characteristics were enough to eliminate the noise from sensor signal. According to the experimental results, the linearity coefficients of the output voltage to oxygen partial pressure for each sensor electrode of six cathode type oxygen sensor are 0.998, 0.997, 0.998, 0.997, 0.997, 0.997 respectively, and the response times are all within 4 minutes.

• 한국컴퓨터산업학회논문지
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• 제8권2호
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• pp.123-130
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• 2007

본 논문에서는 신호조정 회로로서 필수적인 다중 채널 심장 전기도 전치 증폭기를 제작하기 위한 설계조건의 분석 및 전기 회로적 해석을 수행하였다. 설계된 회로는 기존의 64 채널의 공간 분해능을 향상시키기 위하여 128채널로 구성하였으며, 전치증폭기는 입력회로부, 차동증폭부, 오른다리구동회로 및 주증폭기의 노치필터로 구성되도록 설계하였다.