Low noise resistive analog front-end with automatic offset calibration loop

Kim, Hyungseup; Song, Hyoung Woon; Park, Yunjong; Ko, Hyoungho

doi:10.1109/isocc.2015.7401732

Cited by 3 publications

(4 citation statements)

References 1 publication

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“…Figure 6(b) showcases the CMFB. To compensate for the frequency response within the HFP, a nested Miller compensation technique is employed [25].…”

Section: 𝑉𝑅𝑖𝑝𝑝𝑙𝑒 𝑜𝑢𝑡 ≈ 𝑉𝑅𝑖𝑝𝑝𝑙𝑒mentioning

confidence: 99%

Biopotential multi-path current feedback instrumentation amplifier with automatic offset cancellation loop for resistive bridge microsensors

Laababid,

El Khadiri,

Tahiri

2023

IJPEDS

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<span lang="EN-US">This study introduces a refined current feedback instrumentation amplifier (CFIA) specifically designed for amplifying biopotential signals that originate from resistive-bridge sensors. The proposed architecture uniquely incorporates a multipath chopper-stabilized CFIA which has been developed to minimize the effects of bridge offsets, while maintaining low power usage, high input impedance, and reduced noise characteristics. The engineering blueprint employs a ripple reduction loop (RRL) to mitigate output ripple caused by chopper up-modulation. To speed up offset cancellation and to limit the offset caused by bridge mismatch, an automatic offset cancellation loop (AOCL) circuit is integrated within the analog front end (AFE). Crafted using a conventional 0.18 µm CMOS process, the CFIA in this design provides adjustable gain between 20.35 dB to 55.14 dB, with a power supply rejection ratio (PSRR) and a common mode rejection ratio (CMRR) of 103 dB and 114 dB, respectively. The system demonstrates an input-referred noise (IRN) value of 16 ηV/√Hz at 200 Hz frequency, equivalent to a noise efficiency factor (NEF) of 5.18. Operating from a supply voltage of 1.8V, the AFE shows a power consumption of 291 μW.</span>

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“…Figure 6(b) showcases the CMFB. To compensate for the frequency response within the HFP, a nested Miller compensation technique is employed [25].…”

Section: 𝑉𝑅𝑖𝑝𝑝𝑙𝑒 𝑜𝑢𝑡 ≈ 𝑉𝑅𝑖𝑝𝑝𝑙𝑒mentioning

confidence: 99%

Biopotential multi-path current feedback instrumentation amplifier with automatic offset cancellation loop for resistive bridge microsensors

Laababid,

El Khadiri,

Tahiri

2023

IJPEDS

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“…However, the offset in the resistive bridge still remains. To adjust the offset in the bridge, the automatic offset calibration loop circuit (AOCL) is designed [26], as shown in Fig. 8.…”

Section: Auto Offset Calibration Loopmentioning

confidence: 99%

Low-Noise Resistive Bridge Sensor Analog Front-End Using Chopper-Stabilized Multipath Current Feedback Instrumentation Amplifier and Automatic Offset Cancellation Loop

et al. 2022

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Resistive bridge sensors are used in many application areas to measure changes in physical parameters. To amplify the resistive changes from sensing elements with high precision, various offset contributors in the resistive bridge and amplifiers should be minimized. This study proposes a low-noise resistive bridge sensor analog front-end (AFE) using a chopper-stabilized multipath current feedback instrumentation amplifier (CFIA) and an automatic offset cancellation loop. The proposed circuit exploits a multipath chopper-stabilized architecture for obtaining low noise performance and wide bandwidth characteristics. This circuit can minimize the offsets in the bridge and the high frequency and low frequency amplifiers, while achieving high precision resistive signal acquisition. The high frequency path of the multipath amplifier uses the CFIA topology with class-AB output stage. The offset in the high frequency path is stabilized by the low frequency path amplifier with a high gain and low noise chopper amplifier. The up-modulated offset in the low frequency chopper amplifier path is reduced by the AC-coupled ripple reduction loop (RRL). An automatic offset calibration loop (AOCL) circuit was designed to calibrate the offset due to the bridge mismatch. The AOCL reduces the bridge offset using a successive approximation register (SAR)-based binary-search algorithm. The gain of the proposed circuit is adjustable from 15.56 dB to 44.14 dB. The AFE is implemented in a 0.18 μm CMOS process and draws 123 μA current from a 3.3 V supply. The input referred noise and noise efficiency factor (NEF) are 14.6 nV/√Hz and 6.1, respectively.INDEX Resistive analog front-end, current feedback instrumentation amplifier (CFIA), multipath amplifier, automatic offset calibration loop (AOCL)

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“…The ACB is the DC voltage gain of the NMOS cascode in the CB. The output of the CB through A6 is combined to estimate the amount of ripple suppressed by the current adder, as given by Equation (6). The simulation results of the ripple for V x when a 10-mV offset exists are shown in Figure 5.…”

Section: Ripple Reduction Loop Designmentioning

confidence: 99%

“…Sensing diminutive signals with a small output current and small output voltage amplitude using MEMS sensors requires large amplification. Therefore, high gain, high input impedance, and low-noise operational amplification are essential for various sensor interfaces [5][6][7]. To reduce output noise, chopper stabilization or auto-zeroing techniques are typically used [8].…”

Section: Introductionmentioning

confidence: 99%

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

Kim

Han

et al. 2019

Applied Sciences

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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.

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Low noise resistive analog front-end with automatic offset calibration loop

Cited by 3 publications

References 1 publication

Biopotential multi-path current feedback instrumentation amplifier with automatic offset cancellation loop for resistive bridge microsensors

Biopotential multi-path current feedback instrumentation amplifier with automatic offset cancellation loop for resistive bridge microsensors

Low-Noise Resistive Bridge Sensor Analog Front-End Using Chopper-Stabilized Multipath Current Feedback Instrumentation Amplifier and Automatic Offset Cancellation Loop

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

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