A CMOS inverter-based class-AB pseudo-differential amplifier with current-mode common-mode feedback (CMFB)

Suadet, Apirak; Kasemsuwan, Varakorn

doi:10.1007/s10470-012-9970-0

Cited by 6 publications

(3 citation statements)

References 27 publications

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“…Thus, the power consumption can be reduced by designing A2 with relaxed specifications. The A0 is implemented using a fully differential, three stage opamp [28] for low power supply (1-V), as the noise constraints are easily met by its output swing (>70% of V DD ) with switched capacitor common mode feedback (SCCMFB) circuit. The schematic of three stage opamp (A0) is shown in Fig.…”

Section: Opampsmentioning

confidence: 99%

A 159 μW, Fourth Order, Feedforward, Mutli-bit Sigma Delta Modulator for 100 kHz Bandwidth Image Sensors in 65-nm CMOS Process

Prasad¹,

Patri²,

Bashir³

2018

RADIOENGINEERING

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A fourth-order, three-stage, feedforward cascade sigma-delta modulator (ƩΔM) for CMOS image sensor applications is realized in low leakage, high threshold voltage 65 nm CMOS standard process. A top down CAD methodology is used for the design of building blocks, which involves statistical and simulation optimization at different stages of modulator. The multi-bit ƩΔ architecture employs OTA sharing technique with the dual integrating scheme at the first stage and the gain boosted pseudo-differential class-C inverters as OTAs for the rest two stages for low area and power consumption. The operation of proposed ƩΔM is validated through post-layout simulations, considering worst case. The ƩΔM operates at a power supply of 1-V offering a peak signal-to-ratio of 92 dB and a peak signal-to-noise plus distortion ratio of 89 dB for a signal bandwidth of 100 kHz. The overall power and estimated area consumed by the ƩΔM including auxiliary blocks is 159 µW and 101.2 mm 2 , respectively.

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Section: Opampsmentioning

confidence: 99%

A 159 μW, Fourth Order, Feedforward, Mutli-bit Sigma Delta Modulator for 100 kHz Bandwidth Image Sensors in 65-nm CMOS Process

Prasad¹,

Patri²,

Bashir³

2018

RADIOENGINEERING

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“…Class AB amplifiers used in switched-capacitor applications often use a switched-capacitor CMFB [7,[23][24][25], which dissipates dynamic power, and could require an additional error amplifier. Alternative solutions use a resistive [26] or capacitive [13] divider followed by an error amplifier, or use a differential difference amplifier [27]: in all cases, static current is required, increasing power consumption. A CMFB architecture that does not requires additional power exists, and is the triode CMFB [28], where MOS transistors operating in the triode region are used to sense the output common-mode voltage and control the gain of a current mirror.…”

Section: Common-mode Feedback For Class-ab Otasmentioning

confidence: 99%

Comparative performance analysis and complementary triode based CMFB circuits for fully differential class AB symmetrical OTAs with low power consumption

Centurelli

Monsurrò

Trifiletti

2015

Circuit Theory & Apps

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SUMMARYIn this paper we extend the figures of merit for class AB symmetrical OTAs to the fully differential case and compare topologies from the literature. This analysis shows that the power consumption of the CMFB can have a significant role in determining the efficiency of the OTA, but on the other hand a CMFB is needed both to set the desired output common mode voltage and to improve the CMRR. We propose the complementary triode CMFB, i.e. a triode CMFB applied both at the NMOS and PMOS current mirrors, as suitable for class AB symmetrical OTAs, and show some case studies in deep submicron CMOS technology to assess the effectiveness of the proposed solution.

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“…Even if all these innovative techniques are very interesting from a research point of view, the most common approach to implementing analog building blocks suitable for automatic place and route exploits the digital standard cells as basic analog amplifiers [32][33][34][35][36][37]. In fact, the simplest digital gate (the inverter) behaves as a common source amplifier [38], and several inverter-based OTAs [39][40][41][42][43][44][45][46][47][48][49][50] have been proposed in the literature. However, differently from custom-designed inverters, the standard-cell inverter is typically optimized for area footprint or symmetrical slew rate, and as a consequence, it exhibits a systematic offset in its input-output dc transfer characteristic which impacts the output static voltage and strongly degrades the performance of standard-cell-based cascaded amplifiers.…”

Section: Introductionmentioning

confidence: 99%

A Standard-Cell-Based CMFB for Fully Synthesizable OTAs

Centurelli

Sala

Scotti

2022

JLPEA

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In this paper, we propose a fully standard-cell-based common-mode feedback (CMFB) loop with an explicit voltage reference to improve the CMRR of pseudo-differential standard-cell-based amplifiers and to stabilize the dc output voltage. This latter feature allows robust biasing of operational transconductance amplifiers (OTAs) based on a cascade of such stages. A detailed analysis of the CMFB is reported to both provide insight into circuit behavior and to derive useful design guidelines. The proposed CMFB is then exploited to build a fully standard-cell OTA suitable for automatic place and route. Simulation results referring to the standard-cell library of a commercial 130 nm CMOS process illustrated a differential gain of 28.3 dB with a gain-bandwidth product of 15.4 MHz when driving a 1.5 pF load capacitance. The OTA exhibits good robustness under PVT and mismatch variations and achieves state-of-the-art FOMs also thanks to the limited area footprint.

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A CMOS inverter-based class-AB pseudo-differential amplifier with current-mode common-mode feedback (CMFB)

Cited by 6 publications

References 27 publications

A 159 μW, Fourth Order, Feedforward, Mutli-bit Sigma Delta Modulator for 100 kHz Bandwidth Image Sensors in 65-nm CMOS Process

A 159 μW, Fourth Order, Feedforward, Mutli-bit Sigma Delta Modulator for 100 kHz Bandwidth Image Sensors in 65-nm CMOS Process

Comparative performance analysis and complementary triode based CMFB circuits for fully differential class AB symmetrical OTAs with low power consumption

A Standard-Cell-Based CMFB for Fully Synthesizable OTAs

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