• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.206-211
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• 2005

The hearing aids specific operational amplifier described in this paper is a single-supply, low voltage CMOS amplifier. It works on 1.3V single-supply and gets a gain of 82dB. The 0.18${\mu}m$ CMOS process was chosen to reduce the driven voltage as well as the power dissipation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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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.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.483-484
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• 2007

In this paper, we describe a chip design technique for instrumentation amplifier using a nested-chopping technique. Conventional chopping technique uses a pair of chopper, but nested chopping technique uses two pairs of chopper to reduce residual offset and 1/f noise. The inner chopper pair removes the 1/f noise, while the outer chopper pair reduces the residual offset. Our instrumentation amplifier using a nested chopping technique has residual offset under 100 nV. We also implement very low frequency filter. Since this filter needs very large RC time constant, we use a technique named 'diode connected PMOS' to increase R with small die area. The total power consumption is 3.1 mW at the supply voltage of 3.3V with the 0.35um general CMOS technology. The die area of implemented chip was $530um{\times}300um$.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.11
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• pp.41-47
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• 2011

A novel digital instrumentation amplifier(DIA) converting universal signal inputs into 5V voltage-output for industry standard sensor signal processing was designed. The circuit consists of a commercial instrumentation amplifier, seven analog switches, two voltage references of 1.0V and -10.0V, and four resistors. The converting principle is the circuit reconstruction by switches for resistor values and reference voltages according to input signals. The simulation result shows that the DIA has a good output voltage characteristics of 0~5V for the input voltage of 0V~5V, 1V~5V, -10V~+10V, and 4mA~20mA. The nonlinearity error was less than 0.1% for the four type signal inputs.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.5
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• pp.143-152
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• 2004

A novel low-power wideband bipolar second-generation current conveyors(CCIIs) and its application to universal instrumentation amplifier(UIA) were proposed. The CCII for accuracy voltage or current transfer characteristics and low current input impedance adopted adaptive current bias circuit into conventional class Ab CCII. The UIA consists of only two CCIIs and four resistors. Three instrumentation function of the UIA can be realized by selection of input signals and resistors. The simulation results show that the CCII has input impedance of 2.0$\Omega$ and the voltage gain of 60㏈ for frequency range from 0 to 50KHz when used as a voltage amplifier. The CCII has also good characteristics of current follower for current range from -100㎃ to ＋100㎃. The simulation results show that the UIA has three instrumentation amplifier functions without resistor matching. The UIA has the voltage gain of 40㏈ for frequency range from 0 to 100KHz when used as a fully-differential instrumentation amplifier. The power dissipations of the CCII and the UIA are 0.75㎽ and 1.5㎽ at supply voltage of $\pm$2.5V, respectively.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.3
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• pp.44-53
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• 2008

In this paper, we present the design of delta-sigma modulation-based class-D amplifier for driving headphones in portable audio applications. The presented class-D amplifier generates PWM(pulse width modulation) signals using a single-bit fourth-order high-performance delta-sigma modulator. To achieve a high SNR(signal-to-noise ratio) and ensure system stability, the locations of the modulator loop filter poles and zeros are optimized and thoroughly simulated. The test chip is fabricated using a standard $0.18{\mu}m$ CMOS process. The active area of the chip is $1.6mm^2$. It operates for the signal bandwidth from 20Hz to 20kHz. The measured THD+N(total harmonic distortion plus noise) at the $32{\Omega}$ load terminal is less than 0.03% from a 3V power supply.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.1
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• pp.59-67
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• 2016

A novel instrumentation amplifier (IA) using fully-differential linear operational transconductance amplifier (FLOTA) for electronic measurement systems with low cost, wideband, and gain control with wide range is designed. The IA consists of a FLOTA, two resistor, and an operational amplifier(op-amp). The principal of the operating is that the difference of two input voltages applied into FLOTA converts into two same difference currents, and then these current drive resistor of (+) terminal and feedback resistor of op-amp to obtain output voltage. To verify operating principal of the IA, we designed the FLOTA and realized the IA used commercial op-amp LF356. Simulation results show that the FLOTA has linearity error of 0.1% and offset current of 2.1uA at input dynamic range ${\pm}3.0V$. The IA had wide gain range from -20dB to 60dB by variation of only one resistor and -3dB frequency for the 60dB was 10MHz. The proposed IA also has merits without matching of external resistor and controllable offset voltage using the other resistor. The power dissipation of the IA is 105mW at supply voltage of ${\pm}5V$.

• Journal of Semiconductor Engineering
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• v.2 no.1
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• pp.109-118
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• 2021

This review paper describes the overall operating principle of a discrete-time delta-sigma modulator (DTDSM) and a continuous-time delta-sigma modulator (CTDSM) using a switched-capacitor (SC). In addition, research that has solved the problems related to each delta-sigma modulator (DSM) is introduced, and the latest developments are explained. This paper describes the chopper-stabilization technique that mitigates flicker noise, which is crucial for the DSM. In the case of DTDSM, this paper addresses the problems that arise when using SC circuits and explains the importance of the operational transconductance amplifier performance of the first integrator of the DSM. In the case of CTDSM, research that has reduced power consumption, and addresses the problems of clock jitter and excess loop delay is described. The recent developments of the analog front end, which have become important due to the increasing use of wireless sensors, is also described. In addition, this paper presents the advantages and disadvantages of the three-opamp instrumentation amplifier (IA), current feedback IA (CFIA), resistive feedback IA, and capacitively coupled IA (CCIA) methods for implementing instrumentation amplifiers in AFEs.

• Journal of Sensor Science and Technology
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• v.32 no.6
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• pp.432-440
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• 2023

This study introduces an efficient readout circuit designed for two-electrode electrocardiogram (ECG) recording, characterized by its low-noise and low-power consumption attributes. Unlike its three-electrode counterpart, the two-electrode ECG is susceptible to common-mode interference (CMI), causing signal distortion. To counter this, the proposed circuit integrates a common-mode charge pump (CMCP) with a window comparator, allowing for a CMI tolerance of up to 20 V_PP. The CMCP design prevents the activation of electrostatic discharge (ESD) diodes and becomes operational only when CMI surpasses the predetermined range set by the window comparator. This ensures power efficiency and minimizes intermodulation distortion (IMD) arising from switching noise. To maintain ECG signal accuracy, the circuit employs a chopper-stabilized instrumentation amplifier (IA) for low-noise attributes, and to achieve high input impedance, it incorporates a floating high-pass filter (HPF) and a current-feedback instrumentation amplifier (CFIA). This comprehensive design integrates various components, including a QRS peak detector and serial peripheral interface (SPI), into a single 0.18-㎛ CMOS chip occupying 0.54 mm². Experimental evaluations showed a 0.59 µV_RMS noise level within a 1-100 Hz bandwidth and a power draw of 23.83 µW at 1.8 V.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.80-87
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• 2013

A novel instrumentation amplifier(IA) using positive polarity current-conveyor(CCII+) for electronic measurement systems with low cost, wideband, and gain control with wide range is designed. The IA consists of two CCII+, three resistor, and an operational amplifier(op-amp). The principal of the operating is that the difference of two input voltages applied into two CCII+ used voltage and current follower converts into same currents, and then these current drive resistor of (+) terminal and feedback resistor of op-amp to obtain output voltage. To verify operating principal of the IA, we designed the CCII+ and used commercial op-amp LF356. Simulation results show that voltage follower used CCII+ has offset voltage of 0.21mV at linear range of ${\pm}$4V. The IA had wide gain range from -20dB to 60dB by variation of only one resistor and -3dB frequency for the gain of 60dB was 400kHz. The IA also has merits without matching of external resistor and controllable offset voltage using the other resistor. The power dissipation of the IA is 130mW at supply voltage of ${\pm}$5V.