scholarly journals High-CMRR Low-Noise Fully Integrated Front-End for EEG Acquisition Systems

Electronics ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1157 ◽  
Author(s):  
Robert Chebli ◽  
Mohamed Ali ◽  
Mohamad Sawan
Keyword(s):  
Low Noise ◽  
Common Mode ◽  
Fully Integrated ◽  
Dc Offset ◽  
Chopper Stabilization ◽  
Logarithmic Amplifier ◽  
Offset Voltage ◽  
High Cmrr ◽  
Programmable Gain ◽  
Stabilization Technique

We present in this paper a fully integrated low-noise high common-mode rejection ratio (CMRR) logarithmic programmable gain amplifier (LPGA) and chopped LPGA circuits for EEG acquisition systems. The proposed LPGA is based on a rail-to-rail true logarithmic amplifier (TLA) stage. The high CMRR achieved in this work is a result of cascading three amplification stages to construct the LPGA in addition to the lower common-mode gain of the proposed logarithmic amplification topology. In addition, the 1 / f noise and the inherent DC offset voltage of the input transistors are reduced using a chopper stabilization technique. The CMOS 180 nm standard technology is used to implement the circuits. Experimental results for the integrated LPGA show a CMRR of 140 dB, a differential gain of 37 dB, an input-referred noise of 0.754 μ Vrms, a 189 μ W power consumption from 1.8 V power supply and occupies an active area of 0.4 mm 2 .

A Low-Noise, Low-Power, Wide Dynamic Range Logarithmic Amplifier for Biomedical Applications

2018 ◽  
Vol 27 (07) ◽  
pp. 1850104 ◽  
Author(s):  
Yuwadee Sundarasaradula ◽  
Apinunt Thanachayanont
Keyword(s):  
Low Power ◽  
Biomedical Applications ◽  
Dynamic Range ◽  
Supply Voltage ◽  
Low Noise ◽  
Power Supply Voltage ◽  
Wide Dynamic Range ◽  
Dc Offset ◽  
Limiting Amplifier ◽  
Logarithmic Amplifier

This paper presents the design and realization of a low-noise, low-power, wide dynamic range CMOS logarithmic amplifier for biomedical applications. The proposed amplifier is based on the true piecewise linear function by using progressive-compression parallel-summation architecture. A DC offset cancellation feedback loop is used to prevent output saturation and deteriorated input sensitivity from inherent DC offset voltages. The proposed logarithmic amplifier was designed and fabricated in a standard 0.18[Formula: see text][Formula: see text]m CMOS technology. The prototype chip includes six limiting amplifier stages and an on-chip bias generator, occupying a die area of 0.027[Formula: see text]mm2. The overall circuit consumes 9.75[Formula: see text][Formula: see text]W from a single 1.5[Formula: see text]V power supply voltage. Measured results showed that the prototype logarithmic amplifier exhibited an 80[Formula: see text]dB input dynamic range (from 10[Formula: see text][Formula: see text]V to 100[Formula: see text]mV), a bandwidth of 4[Formula: see text]Hz–10[Formula: see text]kHz, and a total input-referred noise of 5.52[Formula: see text][Formula: see text]V.

Design of High-SNR CMOS Interface Circuit for Micro-Machined Gyroscope

2011 ◽  
Vol 483 ◽  
pp. 508-512
Author(s):  
Hai Xi Lu ◽  
Yong Ping Xu ◽  
Shou Rong Wang
Keyword(s):  
High Gain ◽  
Low Noise ◽  
Sigma Delta Modulator ◽  
Sigma Delta ◽  
Interface Circuit ◽  
Fully Differential ◽  
Chopper Stabilization ◽  
Front End ◽  
Cascade Structure ◽  
Stabilization Technique

A CMOS integrated interface circuit for micro-machined gyroscope containing a novel front-end and 6th-order Sigma-delta modulator is presented in this paper. To reduce the noise coming from the sensor and circuit, the front-end is accomplished by a switched-capacitor architecture, which constructed by a high-gain fully-differential amplifier and improved by chopper-stabilization technique, and work under a designed charging and sampling logic scheme. A cascade 6th-order Sigma-Delta modulator is designed to get high resolution, reduce quantized error and suppress the instability brought by high-order modulator. With the cascade structure and 16-bit resolution 32 OSR, the modulator outputs 3-bits digital stream. The whole circuit is designed with AMS technique and 3.3V power consumption. The simulation result presents that the interface circuit performs a appointed under a low-noise design specification in signal band, and the SNR of the circuit achieves remarkable value of 106dB.

A 3.6 μW 60 nV/sqrtHz Capacitively-Coupled Instrumentation Amplifier for Biopotential Signal Recordings

2015 ◽  
Vol 24 (06) ◽  
pp. 1550089 ◽  
Author(s):  
Yin Zhou ◽  
Xiaobo Wu ◽  
Peng Sun ◽  
Menglian Zhao
Keyword(s):  
Low Power ◽  
Low Noise ◽  
Instrumentation Amplifier ◽  
Cmos Process ◽  
Frequency Noise ◽  
Noise Power ◽  
Current Feedback ◽  
Common Mode ◽  
Capacitively Coupled ◽  
Offset Voltage

This paper presents a low-power low-noise instrumentation amplifier (IA) intended for biopotential signal recordings. The IA is designed based on a capacitively-coupled topology, which achieves wide input common-mode range, high common-mode rejection ratio (CMRR) and low power consumption. To reduce low-frequency noise and output ripple at the same time, a combination of chopping and ping-pong auto-zeroing techniques, which is normally used in current-feedback IAs, is introduced for the capacitively-coupled topology in this paper. An intrinsic adverse effect of the proposed structure which causes additional ripple is analyzed. The DC electrode offset voltage is suppressed and the input impedance is boosted through feedback techniques. An improved switched-capacitor common mode feedback (SC CMFB) circuit is also presented. Test results show that the IA achieves an equivalent input-referred noise power spectrum density of 60 nV/sqrtHz and a noise efficiency factor (NEF) of 5.58. The bandwidth is 0.5 Hz to 10 kHz, covering most biopotential recording applications. The IA was implemented in 0.18-μm CMOS process. It occupies 0.27 mm2 core area and consumes 3.6 μA from a 1 V supply.

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