scholarly journals Low-Noise Chopper-Stabilized Multi-Path Operational Amplifier with Nested Miller Compensation for High-Precision Sensors

2019 ◽  
Vol 10 (1) ◽  
pp. 281 ◽  
Author(s):  
Jaesung Kim ◽  
Hyungseup Kim ◽  
Kwonsang Han ◽  
Donggeun You ◽  
Hyunwoo Heo ◽  
...  
Keyword(s):  
High Precision ◽  
Operational Amplifier ◽  
High Frequency ◽  
Flicker Noise ◽  
Low Frequency ◽  
Low Noise ◽  
Cmos Process ◽  
Miller Compensation ◽  
Chopper Stabilization ◽  
Nested Miller Compensation

This paper presents a low-noise multi-path operational amplifier for high-precision sensors. A chopper stabilization technique is applied to the amplifier to remove offset and flicker noise. A ripple reduction loop (RRL) is designed to remove the ripple generated in the process of up-modulating the flicker noise and offset. To cancel the notch in the overall transfer function due to the RRL operation, a multi-path architecture using both a low-frequency path (LFP) and high-frequency path (HFP) is implemented. The low frequency path amplifier is implemented using the chopper technique and the RRL. In the high-frequency path amplifier, a class-AB output stage is implemented to improve the power efficiency. The transfer functions of the LFP and HFP induce a first-order frequency response in the system through nested Miller compensation. The low-noise multi-path amplifier was fabricated using a 0.18 µm 1P6M complementary metal-oxide-semiconductor (CMOS) process. The power consumption of the proposed low-noise operational amplifier is 0.174 mW with a 1.8 V supply and an active area of 1.18 mm2. The proposed low-noise amplifier has a unit gain bandwidth (UGBW) of 3.16 MHz, an input referred noise of 11.8 nV/√Hz, and a noise efficiency factor (NEF) of 4.46.

Study of a closed-loop high-precision front-end circuit for tunneling magneto-resistance sensors

2019 ◽  
Vol 33 (08) ◽  
pp. 1950085 ◽  
Author(s):  
Xiangyu Li ◽  
Jianping Hu ◽  
Xiaowei Liu
Keyword(s):  
High Precision ◽  
Closed Loop ◽  
Low Frequency ◽  
Cmos Technology ◽  
Low Noise ◽  
Corner Frequency ◽  
Cmos Process ◽  
Interface Circuit ◽  
Front End ◽  
Magneto Resistance

A closed-loop high-precision front-end interface circuit in a standard 0.35 [Formula: see text]m CMOS technology for a tunneling magneto-resistance (TMR) sensor is presented in this paper. In consideration of processing a low frequency and weak geomagnetic signal, a low-noise front-end detection circuit is proposed with chopper technique to eliminate the 1/f noise and offset of operational amplifier. A novel ripple suppression loop is proposed for eliminating the ripple in a tunneling magneto-resistance sensor interface circuit. Even harmonics is eliminated by fully differential structure. The interface is fabricated in a standard 0.35 [Formula: see text]m CMOS process and the active circuit area is about [Formula: see text]. The interface chip consumes 7 mW at a 5 V supply and the 1/f noise corner frequency is lower than 1 Hz. The interface circuit of TMR sensors can achieve a better noise level of [Formula: see text]. The ripple can be suppressed to less than 10 [Formula: see text]V by ripple suppression loop.

A Low Noise Operational Amplifier Design Using Chopper Stability

2013 ◽  
Vol 562-565 ◽  
pp. 1450-1454
Author(s):  
Xiao Wei Liu ◽  
Liang Liu ◽  
Jian Yang ◽  
Song Chen ◽  
Wei Ping Chen
Keyword(s):  
Operational Amplifier ◽  
Low Frequency ◽  
Low Noise ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Op Amp ◽  
Chopper Stabilization ◽  
Amplifier Design

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.

scholarly journals A 5.43 nV/√Hz Chopper Operational Amplifier Using Lateral PNP Input Stage with BJT Current Mirror Base Current Cancellation

2020 ◽  
Vol 10 (23) ◽  
pp. 8376
Author(s):  
Hyungseup Kim ◽  
Yongsu Kwon ◽  
Donggeun You ◽  
Hyun-Woong Choi ◽  
Seong Hyun Kim ◽  
...  
Keyword(s):  
Operational Amplifier ◽  
Low Frequency ◽  
Low Noise ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Cmos Process ◽  
Current Mirror ◽  
Input Stage ◽  
Base Current ◽  
Measured Input

This paper presents a low-noise chopper operational amplifier using a lateral PNP input stage with bipolar junction transistor (BJT) current mirror base current cancellation. The BJT has a lower noise characteristic than the metal–oxide–semiconductor (MOS) transistor, where low-noise characteristics can be achieved by implanting the BJT to the input stage of the amplifier; however, the base current of the BJT input stage causes low input impedance of the amplifier. The BJT current mirror base current cancellation technique is implemented to enhance the input impedance of the BJT input stage by canceling the base current. BJT current mirror base current cancellation is implemented with a simple scheme using NPN transistors with deep n-well in a generic complementary metal–oxide–semiconductor (CMOS) process. For further noise reduction with the BJT input stage, a chopper amplifier scheme is adopted to reduce low-frequency components such as 1/f noise terms in the low-frequency range. The prototype chip is fabricated in a 0.18-μm CMOS process. The active area of the prototype amplifier is 0.213 mm2. The measured input-referred noise is 5.43 nV/√Hz. The measured input base current of the amplifier with base current cancellation is 67.971 nA. The total amplifier current consumption is 278.3 μA, with a power supply of 3.3 V.

scholarly journals Fusion of GNSS and Speedometer Based on VMD and Its Application in Bridge Deformation Monitoring

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 694 ◽  
Author(s):  
Ruicheng Zhang ◽  
Chengfa Gao ◽  
Shuguo Pan ◽  
Rui Shang
Keyword(s):  
Real Time ◽  
High Precision ◽  
High Frequency ◽  
Spectral Response ◽  
Low Frequency ◽  
Deformation Monitoring ◽  
Full Time ◽  
Dynamic Displacement ◽  
Mode Decomposition ◽  
Acceleration Sensors

Real-time dynamic displacement and spectral response on the midspan of Jiangyin Bridge were calculated using Global Navigation Satellite System (GNSS) and a speedometer for the purpose of understanding the dynamic behavior and the temporal evolution of the bridge structure. Considering that the GNSS measurement noise is large and the velocity/acceleration sensors cannot measure the low-frequency displacement, the Variational Mode Decomposition (VMD) algorithm was used to extract the low-frequency displacement of GNSS. Then, the low-frequency displacement extracted from the GNSS time series and the high-frequency vibration calculated by speedometer were combined in this paper in order to obtain the high precision three-dimensional dynamic displacement of the bridge in real time. Simulation experiment and measured data show that the VMD algorithm could effectively resist the modal aliasing caused by noise and discontinuous signals compared with the commonly used Empirical Mode Decomposition (EMD) algorithm, which is guaranteed to get high-precision fusion data. Finally, the fused displacement results can identify high-frequency vibrations and low-frequency displacements of a mm level, which can be used to calculate the spectral characteristics of the bridge and provide reference to evaluate the dynamic and static loads, and the health status of the bridge in the full frequency domain and the full time domain.

scholarly journals A Linearity Improvement Front End with Subharmonic Current Commutating Passive Mixer for 2.4 GHz Direct Conversion Receiver in 0.13 μm CMOS Technology

Electronics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1369
Author(s):  
Dongquan Huo ◽  
Luhong Mao ◽  
Liji Wu ◽  
Xiangmin Zhang
Keyword(s):  
Power Consumption ◽  
Flicker Noise ◽  
Analytical Formula ◽  
Direct Conversion ◽  
Low Noise ◽  
Cmos Process ◽  
Passive Mixer ◽  
Dc Offset ◽  
Front End ◽  
Rf Front End

Direct conversion receiver (DCR) architecture is a promising candidate in the radio frequency (RF) front end because of its low power consumption, low cost and ease of integration. However, flicker noise and direct current (DC) offset are large issues. Owing to the local oscillator (LO) frequency, which is half of the RF frequency, and the absence of a DC bias current that introduces no flicker noise, the subharmonic passive mixer (SHPM) core topology front end overcomes the shortcoming effectively. When more and more receivers (RX) and transmitters (TX) are integrated into one chip, the linearity of the receiver front end becomes a very important performer that handles the TX and RX feedthrough. Another reason for the requirement of good linearity is the massive electromagnetic interference that exists in the atmosphere. This paper presents a linearity-improved RF front end with a feedforward body bias (FBB) subharmonic mixer core topology that satisfies modern RF front end demands. A novel complementary derivative superposition (DS) method is presented in low noise amplifier (LNA) design to cancel both the third- and second-order nonlinearities. To the best knowledge of the authors, this is the first time FBB technology is used in the SHPM core to improve linearity. A Volterra series is introduced to provide an analytical formula for the FBB of the SHPM core. The design was fabricated in a 0.13 μm complementary metal oxide semiconductor (CMOS) process with a chip area of 750 μm × 1270 μm. At a 2.4 GHz working frequency, the measurement result shows a conversion gain of 36 dB, double side band (DSB) noise figure (NF) of 6.8 dB, third-order intermodulation intercept point (IIP3) of 2 dBm, LO–RF isolation of 90 dB and 0.8 mW DC offset with 14.4 mW power consumption at 1.2 V supply voltage. These results exhibit better LO–RF feedthrough and DC offset, good gain and NF, moderate IIP3 and the highest figure of merit compared to the state-of-the-art publications.

scholarly journals A 24.88 nV/√Hz Wheatstone Bridge Readout Integrated Circuit with Chopper-Stabilized Multipath Operational Amplifier

2020 ◽  
Vol 10 (1) ◽  
pp. 399 ◽  
Author(s):  
Kwonsang Han ◽  
Hyungseup Kim ◽  
Jaesung Kim ◽  
Donggeun You ◽  
Hyunwoo Heo ◽  
...  
Keyword(s):  
Integrated Circuit ◽  
Operational Amplifier ◽  
Wheatstone Bridge ◽  
Input Resistance ◽  
Cmos Technology ◽  
Low Noise ◽  
Oxide Semiconductor ◽  
Instrumentation Amplifier ◽  
Readout Integrated Circuit ◽  
Chopper Stabilization

This paper proposes a low noise readout integrated circuit (IC) with a chopper-stabilized multipath operational amplifier suitable for a Wheatstone bridge sensor. The input voltage of the readout IC changes due to a change in input resistance, and is efficiently amplified using a three-operational amplifier instrumentation amplifier (IA) structure with high input impedance and adjustable gain. Furthermore, a chopper-stabilized multipath structure is applied to the operational amplifier, and a ripple reduction loop (RRL) in the low frequency path (LFP) is employed to attenuate the ripple generated by the chopper stabilization technique. A 12-bit successive approximation register (SAR) analog-to-digital converter (ADC) is employed to convert the output voltage of the three-operational amplifier IA into digital code. The Wheatstone bridge readout IC is manufactured using a standard 0.18 µm complementary metal-oxide-semiconductor (CMOS) technology, drawing 833 µA current from a 1.8 V supply. The input range and the input referred noise are ±20 mV and 24.88 nV/√Hz, respectively.

scholarly journals High-Precision Acceleration Measurement System Based on Tunnel Magneto-Resistance Effect

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1117 ◽  
Author(s):  
Lu Gao ◽  
Fang Chen ◽  
Yingfei Yao ◽  
Dacheng Xu
Keyword(s):  
Magnetic Field ◽  
High Precision ◽  
Measurement System ◽  
Frequency Modulation ◽  
High Frequency ◽  
Low Noise ◽  
Acceleration Measurement ◽  
Field Source ◽  
Modulation Technique ◽  
Magneto Resistance

A high-precision acceleration measurement system based on an ultra-sensitive tunnel magneto-resistance (TMR) sensor is presented in this paper. A “force–magnetic–electric” coupling structure that converts an input acceleration into a change in magnetic field around the TMR sensor is designed. In such a structure, a micro-cantilever is integrated with a magnetic field source on its tip. Under an acceleration, the mechanical displacement of the cantilever causes a change in the spatial magnetic field sensed by the TMR sensor. The TMR sensor is constructed with a Wheatstone bridge structure to achieve an enhanced sensitivity. Meanwhile, a low-noise differential circuit is developed for the proposed system to further improve the precision of the measured acceleration. The experimental results show that the micro-system achieves a measurement resolution of 19 μg/√Hz at 1 Hz, a scale factor of 191 mV/g within a range of ± 2 g, and a bias instability of 38 μg (Allan variance). The noise sources of the proposed system are thoroughly investigated, which shows that low-frequency 1/f noise is the dominant noise source. We propose to use a high-frequency modulation technique to suppress the 1/f noise effectively. Measurement results show that the 1/f noise is suppressed about 8.6-fold at 1 Hz and the proposed system resolution can be improved to 2.2 μg/√Hz theoretically with this high-frequency modulation technique.

scholarly journals A Wideband Noise and Harmonic Distortion Canceling Low-Noise Amplifier for High-Frequency Ultrasound Transducers

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8476
Author(s):  
Yuxuan Tang ◽  
Yulang Feng ◽  
He Hu ◽  
Cheng Fang ◽  
Hao Deng ◽  
...  
Keyword(s):  
High Frequency ◽  
Harmonic Distortion ◽  
Low Noise ◽  
Low Noise Amplifier ◽  
Cmos Process ◽  
Ultrasound Transducers ◽  
High Frequency Ultrasound ◽  
Front End ◽  
Noise Amplifier ◽  
Frequency Ultrasound

This paper presents a wideband low-noise amplifier (LNA) front-end with noise and distortion cancellation for high-frequency ultrasound transducers. The LNA employs a resistive shunt-feedback structure with a feedforward noise-canceling technique to accomplish both wideband impedance matching and low noise performance. A complementary CMOS topology was also developed to cancel out the second-order harmonic distortion and enhance the amplifier linearity. A high-frequency ultrasound (HFUS) and photoacoustic (PA) imaging front-end, including the proposed LNA and a variable gain amplifier (VGA), was designed and fabricated in a 180 nm CMOS process. At 80 MHz, the front-end achieves an input-referred noise density of 1.36 nV/sqrt (Hz), an input return loss (S11) of better than −16 dB, a voltage gain of 37 dB, and a total harmonic distortion (THD) of −55 dBc while dissipating a power of 37 mW, leading to a noise efficiency factor (NEF) of 2.66.

scholarly journals A 1.8 V 18.13 MHz Inverter-Based On-Chip RC Oscillator with Flicker Noise Suppression Using Logic Transition Voltage Feedback

Electronics ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1353
Author(s):  
Junsoo Ko ◽  
Minjae Lee
Keyword(s):  
Phase Noise ◽  
Noise Suppression ◽  
Flicker Noise ◽  
Low Frequency ◽  
Cmos Process ◽  
Delay Compensation ◽  
Circuit Delay ◽  
On Chip ◽  
Voltage Feedback ◽  
Transition Voltage

An inverter-based on-chip resistor capacitor (RC) oscillator with logic transition voltage (LTV) tracking feedback for circuit delay compensation is presented. In order to achieve good frequency stability, the proposed technique considers the entire inverter chain as a comparator block and changes the LTV to control the oscillation frequency. Furthermore, the negative feedback structure also reduces low-frequency offset phase noise. With a 1.8 V supply and at room temperature, the suggested oscillator operates at 18.13 MHz, consuming 245.7 μ W. Compared to the free-running case, the proposed technique reduces phase noise by 7.7 dB and 5.45 dB at 100 Hz and 1 kHz, respectively. The measured phase noise values are −60.09 dBc/Hz at 1 kHz with a figure of merit (FOM) of 151.35 dB/Hz, and −106.27 dBc/Hz at 100 KHz with an FOM of 157.53 dBc/Hz. The proposed oscillator occupies 0.056 mm2 in a standard 0.18 μ m CMOS process.

scholarly journals Improving the Signal to Noise Ratio of QTF Preamplifiers Dedicated for QEPAS Applications

2020 ◽  
Vol 10 (12) ◽  
pp. 4105
Author(s):  
Piotr Z. Wieczorek ◽  
Tomasz Starecki ◽  
Frank K. Tittel
Keyword(s):  
Operational Amplifier ◽  
Narrow Band ◽  
Signal To Noise Ratio ◽  
Low Frequency ◽  
Electrical Signal ◽  
Low Noise ◽  
Detection Sensitivity ◽  
Noise Amplitude ◽  
Signal To Noise ◽  
Noise Ratio

The signal-to-noise ratio (SNR) is a major factor that limits the detection sensitivity of quartz-enhanced photoacoustic spectroscopy (QEPAS) sensors. The higher the electrical signal level compared to the noise amplitude is the lower the concentration of gases that can be detected. For this reason the preamplifier circuits used in QEPAS should be optimized for low-frequency narrow-band applications. Moreover, special care should be taken when choosing a particular operational amplifier in either a transimpedance or voltage (differential) configuration. It turns out that depending on the preamp topology different operational amplifier parameters should be carefully considered when a high SNR of the whole QEPAS system is required. In this article we analyzed the influence of the crucial parameters of low-noise operational preamplifiers used in QEPAS applications and show the resulting limitations of transimpedance and voltage configurations.

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