A FAST AND LOW SETTLING ERROR CONTINUOUS-TIME COMMON-MODE FEEDBACK CIRCUIT BASED ON DIFFERENTIAL DIFFERENCE AMPLIFIER

2014 ◽  
Vol 23 (05) ◽  
pp. 1450065 ◽  
Author(s):  
TOHID MORADI KHANESHAN ◽  
SAEED NAGHAVI ◽  
MOJDE NEMATZADE ◽  
KHAYROLLAH HADIDI ◽  
ADIB ABRISHAMIFAR ◽  
...  
Keyword(s):  
Continuous Time ◽  
High Speed ◽  
Cmos Technology ◽  
Common Mode ◽  
Op Amp ◽  
Wide Range ◽  
Differential Difference Amplifier ◽  
Unity Gain ◽  
Folded Cascode ◽  
Speed And Accuracy

A high-speed and high-accuracy continuous-time common-mode feedback block (CMFB) is presented. To satisfy speed and accuracy requirements, some modifications have been applied on differential difference amplifier (DDA) CMFB circuit. The proposed method is applied to a folded cascode op-amp with power supply of 3.3 V. In order to verify the proposed circuit, simulations are done in 0.35 μm standard CMOS technology. In the worst condition when the output common-mode (CM) voltage is initialized to VCC or GND, only 1.1 ns is required to set the output CM voltage on the desired level. Also in a wide range of input CM voltage variations, the deviation of the output CM voltage from reference voltage is less than 6 mV, so simulation results confirm the expected accuracy and speed while simultaneously the proposed CMFB circuit preserves other characteristics of DDA CMFB circuit such as unity gain frequency, 3-dB bandwidth, phase margin and linearity.

scholarly journals Compact Continuous Time Common-Mode Feedback Circuit for Low-Power, Area-Constrained Neural Recording Amplifiers

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 145
Author(s):  
Joon Young Kwak ◽  
Sung-Yun Park
Keyword(s):  
Low Power ◽  
Continuous Time ◽  
Cmos Technology ◽  
Neural Recording ◽  
Low Noise ◽  
Common Mode ◽  
Passive Components ◽  
Fully Differential ◽  
Transconductance Amplifier ◽  
Differential Difference Amplifier

A continuous-time common-mode feedback (CMFB) circuit for low-power, area-constrained neural recording amplifiers is proposed. The proposed CMFB circuit is compact; it can be realized by simply replacing passive components with transistors in a low-noise folded cascode operational transconductance amplifier (FC-OTA) that is one of the most widely adopted OTAs for neural recording amplifiers. The proposed CMFB also consumes no additional power, i.e., no separate CMFB amplifier is required, thus, it fits well to low-power, area-constrained multichannel neural recording amplifiers. The proposed CMFB is analyzed in the implementation of a fully differential AC-coupled neural recording amplifier and compared with that of an identical neural recording amplifier using a conventional differential difference amplifier-based CMFB in 0.18 μm CMOS technology post-layout simulations. The AC-coupled neural recording amplifier with the proposed CMFB occupies ~37% less area and consumes ~11% smaller power, providing 2.67× larger output common mode (CM) range without CM bandwidth sacrifice in the comparison.

scholarly journals Implementation of Power-Efficient Class AB Miller Amplifiers Using Resistive Local Common-Mode Feedback

2021 ◽  
Vol 11 (3) ◽  
pp. 31
Author(s):  
Anindita Paul ◽  
Mario Renteria-Pinon ◽  
Jaime Ramirez-Angulo ◽  
Ricardo Bolaños-Pérez ◽  
Héctor Vázquez-Leal ◽  
...  
Keyword(s):  
Current Efficiency ◽  
Figure Of Merit ◽  
Small Signal ◽  
Common Mode ◽  
Power Efficient ◽  
Class Ab ◽  
Op Amp ◽  
Class A ◽  
Wide Range ◽  
Quiescent Current

An approach to implement single-ended power-efficient static class-AB Miller op-amps with symmetrical and significantly enhanced slew-rate and accurately controlled output quiescent current is introduced. The proposed op-amp can drive a wide range of resistive and capacitive loads. The output positive and negative currents can be much higher than the total op-amp quiescent current. The enhanced performance is achieved by utilizing a simple low-power auxiliary amplifier with resistive local common-mode feedback that increases the quiescent power dissipation by less than 10%. The proposed class AB op-amp is characterized by significantly enhanced large-signal dynamic, static current efficiency, and small-signal figures of merits. The dynamic current efficiency is 15.6 higher, the static current efficiency is 8.9 times higher, and the small-signal figure of merit is 2.3 times higher than the conventional class-A op-amp. A global figure of merit that determines an op-amp’s ultimate speed is 6.33 times higher than the conventional class A op-amp.

scholarly journals A 2.5 Gbps, 10-Lane, Low-Power, LVDS Transceiver in 28 nm CMOS Technology

Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 350 ◽  
Author(s):  
Xu Bai ◽  
Jianzhong Zhao ◽  
Shi Zuo ◽  
Yumei Zhou
Keyword(s):  
Low Power ◽  
High Speed ◽  
Low Voltage ◽  
Cmos Technology ◽  
Common Mode ◽  
Serial Interface ◽  
Common Mode Voltage ◽  
Rail To Rail ◽  
The Common ◽  
28 Nm

This paper presents a 2.5 Gbps 10-lane low-power low voltage differential signaling (LVDS) transceiver for a high-speed serial interface. In the transmitter, a complementary MOS H-bridge output driver with a common mode feedback (CMFB) circuit was used to achieve a stipulated common mode voltage over process, voltage and temperature (PVT) variations. The receiver was composed of a pre-stage common mode voltage shifter and a rail-to-rail comparator. The common mode voltage shifter with an error amplifier shifted the common mode voltage of the input signal to the required range, thereby the following rail-to-rail comparator obtained the maximum transconductance to recover the signal. The chip was fabricated using SMIC 28 nm CMOS technology, and had an area of 1.46 mm2. The measured results showed that the output swing of the transmitter was around 350 mV, with a root-mean-square (RMS) jitter of 3.65 [email protected] Gbps, and the power consumption of each lane was 16.51 mW under a 1.8 V power supply.

Common Mode Feedback Circuits for Low Voltage Fully-Differential Amplifiers

2016 ◽  
Vol 25 (10) ◽  
pp. 1650124 ◽  
Author(s):  
S. Rekha ◽  
T. Laxminidhi
Keyword(s):  
Power Supply ◽  
Continuous Time ◽  
Efficient Solution ◽  
Low Voltage ◽  
Cmos Technology ◽  
Common Mode ◽  
Power Efficient ◽  
Differential Amplifiers ◽  
Fully Differential ◽  
Simulation Results

Continuous time common mode feedback (CMFB) circuits for low voltage, low power applications are proposed. Four circuits are proposed for gate/bulk-driven pseudo-differential transconductors operating on sub-1-V power supply. The circuits are validated for a bulk-driven pseudo-differential transconductor operating on 0.5[Formula: see text]V in 0.18[Formula: see text][Formula: see text]m standard CMOS technology. Simulation results reveal that the proposed CMFB circuits offer power efficient solution for setting the output common mode of the transconductors. They also load the transconductor capacitively offering capacitance of about 1[Formula: see text]fF to tens of femto farads.

scholarly journals A Start-up Assisted Fully Differential Folded Cascode Opamp

2019 ◽  
Vol 28 (10) ◽  
pp. 1950164 ◽  
Author(s):  
R. Nagulapalli ◽  
K. Hayatleh ◽  
S. Barker ◽  
B. Yassine ◽  
S. Zourob ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Positive Feedback ◽  
Cmos Technology ◽  
Gain Bandwidth ◽  
Fully Differential ◽  
Start Up ◽  
Unity Gain ◽  
Folded Cascode ◽  
Current Selection ◽  
Latch Up

This paper explains the hidden positive feedback in a two-stage fully differential amplifier through external feedback resistors and possible DC latch-up during the amplifier start-up. The biasing current selection among the cascade branches has been explained intuitively, with reference to previous literature. To avoid the latch-up problem, irrespective of the transistor bias currents, a novel hysteresis-based start-up circuit is proposed. An 87[Formula: see text]dB, 250[Formula: see text]MHz unity gain bandwidth amplifier has been developed in 65[Formula: see text]nm CMOS Technology and post-layout simulations demonstrate no start-up failures out of 1000 Monte-Carlo (6-Sigma) simulations. The circuit draws 126[Formula: see text][Formula: see text]A from a 1.2[Formula: see text]V supply and occupies the 2184[Formula: see text][Formula: see text]m2 area.

scholarly journals A 75 μW Two-Stage Op-Amp using 0.18μW CMOS Technology for High-Speed Operations

2019 ◽  
Vol 135 (5) ◽  
pp. 1075-1077 ◽  
Author(s):  
K. Shashidhar ◽  
Sreenivasa Rao Ijjada ◽  
B. Naresh
Keyword(s):  
High Speed ◽  
Cmos Technology ◽  
Two Stage ◽  
Op Amp

scholarly journals Design and PVT Analysis of Robust, High Swing Folded Cascode Operational Amplifier

2019 ◽  
Vol 9 (2) ◽  
pp. 114-118
Keyword(s):  
Power Dissipation ◽  
Operational Amplifier ◽  
Low Voltage ◽  
Cmos Technology ◽  
Current Mirror ◽  
Op Amp ◽  
Multistage Amplifiers ◽  
Pvt Variations ◽  
Folded Cascode ◽  
Voltage Swing

The folded cascode operational amplifier (FCOA) designed in this paper is the single-pole operational amplifier (op amp). In this design, the conventional current mirror is replaced with wide swing current mirror to overcome the essential drawback of cascode configuration. In this paper, negative feedback is used to improve the small-signal gain and to ensure better stability than multistage amplifiers. This paper also aims at improving the output voltage swing, power dissipation and robustness of the op amp. The designed FCOA is proficient in achieving 67.44dB gain and 1.77V output swingat typical voltage for 180nm CMOS technology. The FCOA is highly stable with phase margin of 62.58º while dissipating 0.5mW power. This amplifier is further verified for variability analysis for Process, Voltage and Temperature (PVT) variations to check robustness. All together testing is done at 45 different PVT combinations and results are tabulated accordingly. At each corner temperature and voltage are varied for all together nine combinations to properly address the effect of PVT variations. The results shows that the op amp exhibits desired response at four corners (FF, TT, SS, and FS) of process, over -40º to 125º C temperature range. Also it is capable of operating at very low voltage up to 0.9V adequately showing reduction in power dissipation. Thus the designed op amp is low power, high swing and robust towards process, voltage and temperature variations.

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