Papers by Keyword: Operational Amplifier

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Authors: Wei Juan Zhang, Yan Zhao, Ju Wang, Kun Li
Abstract: A band-gap voltage reference applicable for LDO circuit was designed. The band-gap voltage reference with lower change rate and low temperature-drift and high PSRR was acquired, which uses the two stage operational amplifier as the input terminal, and the miller compensation circuit was adopted in order to improve the stability of the voltage reference circuit. The circuit was simulated with Cadence tool and 0.5μm CMOS model. The results show that the reference voltage is 1.2182V, the PSRR of band-gap voltage reference is-76.8dB. The measured results indicated that the designed band-gap voltage reference is prospective for application in LDO circuit.
Authors: Xiao Wei Liu, Liang Liu, Jian Yang, Song Chen, Wei Ping Chen
Abstract: Noise has become a significant bottleneck limiting the performance of the op amp, and chopper stabilization technology [1] is commonly used to reduce the noise of the op amp. The chopper stabilization technology can significantly reduce the low-frequency 1/f noise of op amp, then reducing the total low-frequency noise of op amp. In this paper, we designed a chopper-stabilized low-noise op amp, and used Cadence software for simulation and debugging.
Authors: Jun Yuan, Wei Wang
Abstract: This paper presents a time-to-digital converter (TDC) based built-in self-test (BIST) scheme for operational amplifier (Op Amp). The propagation delay exiting in the transient response of the Op Amp is monitored by the inverter based TDC, and converted into a digital code based on the referenced delay interval of the inverter used in the TDC, as a result, the digital code is finally employed to determine the test rsults. The circuit-level simualtion results of the proposed BIST syetem for a two-stage Op Amp are presented to demonstrated the feasility of the proposed BIST scheme with high fault coverage.
Authors: Xiang Ning Fan, Hao Zheng, Yu Tao Sun, Xiang Yan
Abstract: In this paper, a 12-bit 100MS/s pipelined ADC is designed. Capacitance flip-around structure is used in sample and hold circuit, and bootstrap structure is adopted in sampling switch which has high linearity. Progressively decreasing technology is used to reduce power consumption and circuit area, where 2.5bit/stage structure is used in the first two stages, 1.5bit/stage structure is used for 3rd to 8th stages, and at the end of the circuit is a 2bit-flash ADC. Digital calibration is designed to eliminate the offset of comparators. Switched-capacitor dynamic comparator structure is used to further reduce the power consumption. The ADC is implemented by using TSMC 0.18m CMOS process with die area be 1.23mm×2.3mm. SNDR and SFDR are 65dB and 71.3dB, when sampling at 100MHz sampling clock. The current of the circuit is 96mA under 1.8V power supply.
Authors: M. B. K. Jamal, S. P. Chew, B. I. Khadijah, S. B. M. Noormiza
Abstract: Due to the rise in demand for portable electronic device, low power and low voltage circuit design is extremely important for the appliances like computers, laptops, mobile phones and etc. Low power dissipation results in longer battery life and better integration density. This can be achieved by designing a modified low voltage op amp. The design of low voltage op amp in this paper is the combination of several low voltage analog cells. The modified low power op amp in this paper is built based on low voltage basic op amp. In this paper, the design objective is to achieve certain criteria such as supply voltage as low as 1 V, high gain more than 40 dB, low power consumption and high bandwidth. The use of FGMOS would increase the operating range of op amp through programming the threshold voltage of the FGMOS. This project is simulated using Silvaco Gateway and Expert.
Authors: Ke Ning Wang, Heng Zhao, Wei Wang
Abstract: Current source with high output impedance is a key part in bioelectrical impedance measurement. In this paper, we presented a design of a current source based on the improved Howland current pump circuit. Then the performance of the proposed current source was simulated in Multisim software. The designed current source was implemented and its output impedance was tested. Both the simulated and tested results show that the proposed current source is a good choice for BI measurement.
Authors: Zhan Peng Jiang, Rui Xu, Hai Huang, Chang Chun Dong
Abstract: An rail-to-rail operational amplifier is presented in this paper, which is designed by with two op amp, the first level of the structure is the complementary differential structure which will providing input for the operational amplifier, the second level is designed with the structure of folding cascode to get a high gain. The operational amplifier is designed with the TSMC 0.35u m3.3VCMOS mixed analog-digital technology library. The simulated results show that the operational amplifier has a DC gain of 110dB,a GBW of 9.5MHz,a static power dissipation of 0.95mW,a phase margin of 73°,a voltage slew rate of 8.2V/μS,an input and output range of 0-3.3V,when operating at 3.3V power supply and a 20pF output load.
Authors: Xi Feng Liang, Li Hao Liu
Abstract: Metal-oxide semiconductor gas-sensitive sensors have various advantages as the basic devices of gas detection systems, such as high sensitivity, fast responsibility and low cost, etc. They are widely applied to many fields. Amplifier circuit is an important section of gas detection system. A new type of amplifier circuit including a three-stage operational amplifier was designed in the paper which can effectively eliminate the influence of the follow-up circuit on the sensor output. Theory analysis and experimental simulations were performed. The results show that the output voltage signals have a linear relation with the concentrations of the detected gas.
Authors: Masahiro Masunaga, Shintaroh Sato, Ryoh Kuwana, Isao Hara, Akio Shima
Abstract: The operational amplifier (op-amp) with high gamma irradiation capability of over 30 kGy have been fabricated by 4H-SiC MOSFETs for measuring instruments which are installed in nuclear power plants. The chip size was 0.7 mm x 1.0 mm, and they consisted of five n-channel MOSFETs and three p-channel MOSFETs on the same die. The output waveform after having irradiated 50 kGy at a rate of 60 Gy/hr was amplified without distortion. On the other hand, the offset voltage became unstable when gamma integral dose was beyond 30 kGy and it at 50 kGy increased to +7.2 mV. For reduction of gamma irradiation influence, we proposed the MOSFETs structure which has field plate (FP) electrodes connected to isolation layer electrically. We indicated that the proposal device had the potential of gamma irradiation capability of 100 kGy experimentally.
Authors: Wei Zong, Yu Shan Zhang
Abstract: In order to realize the integration of electronic circuits and avoid the electromagnetic interference between mutual inductance components and periphery circuit, the paper put forward a new kind of coupling element-mutual capacitance components, which were dual with mutual inductance components, according to the duality principle and the gyrator application theory. First of all, the paper used the basic electrical components-operational amplifier, resistance and capacitor to set up the circuit implementation model of mutual capacitance component, and then selected device parameters to execute theory calculation. On the basis of the previous step, a simulation software-PSpice, was used to simulate the model. Finally, comparison of two different groups of simulation data showed the correctness of the circuit model and the feasibility of the mutual capacitance component.
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