Alfio Dario Grasso

University of Catania | UNICT · Department of Electrical, Electronics and Computer Engineering (DIEEI)

This paper investigates CMOS operational transconductance amplifier (OTA) design methodologies suitable for Internet of Things nodes. The use of MOS transistors in the subthreshold of the body terminal for signal input or bias, as well as newer inverter- and digital-based techniques, is considered. Solutions from the authors’ work are utilized as m...

Feedback amplifiers consisting of multiple gain stages are used to establish highly accurate buffered/amplified signals that can drive a wide range of capacitive load (CL). This article models, analyzes, and presents the measurement results of a high-gain four-stage operational transconductance amplifier (OTA) that is able to handle a wide range of...

A bulk-driven operational transconductance amplifier (OTA) suitable for ultralow-power and ultralow-voltage applications is described. The amplifier exploits local positive feedback in the first stage to increase its transconductance. The OTA entails a single Miller capacitor for frequency compensation, thus saving area occupation and improving fre...

In this chapter, two different solutions, mainly devoted to reducing the settling time assuming the same silicon area, are presented and discussed. The first solution makes use of a clock booster that doubles the CP clock amplitude. The second approach relies on an unconventional pumping capacitors sizing, which set them not equal, but following a...

This chapter introduces the original and unconventional use of the CP as an amplifier. The aim was to extend the use of the CP in all those applications where a time-variant signal has to be amplified with its DC component above the positive power supply rail, such as NMOS LDOs or drivers for piezoelectric devices for ultrasound imaging. This innov...

This chapter is focused on the design strategies for very-low-voltage Dickson CP implementations that are particularly suited for the energy harvesting applications. Three innovative solutions are discussed. A first topology exploits for the CTS the combination of NMOS and PMOS transistors with gates connected to internal nodes of the CP, thus enha...

In the previous chapter, we have focused on the Dickson CP topology with ideal switches. However, real CPs differ substantially for the way the switches are implemented. In this chapter, the main Dickson CP topologies are presented. In particular, after a general introduction on the original topologies and the classification of typical strategies t...

This chapter gathers two different solutions aimed to the reduction of the energy consumed by the converter during the wake-up phase. In particular, in the first section, a solution based on the reduction of the voltage amplitude of the clock signal is presented. It represents a simple but very effective design strategy to increase power conversion...

This chapter introduces the Dickson CP and its main design strategies. In particular, after a simplified analysis, which has the aim of explaining the behavior and the potentiality of this kind of circuit, the key CP parameters are presented, and simple circuit models are derived and discussed. Finally, two optimized design procedures for two diffe...

In this paper the design of power management integrated circuits for the energy harvesting of ultrasound waves in implanted biomedical devices is addressed. In particular, the paper focuses on the main building block of the power conversion stage which is represented by the AC/DC converter. After an in-depth analytical description of cross-coupled...

This paper presents and discusses two Dickson charge pumps that are capable of working with a supply voltage lower than the MOS threshold voltage and are particularly suited for energy-constrained applications. Specifically, the paper includes a theoretical analysis of a previous topology introduced by the authors, and then it discusses a novel top...

This work presents a two-stage operational transconductance amplifier suitable for sub-1 V operation. This characteristic is achieved thanks to the adoption of a bulk-driven non-tailed differential pair. Local positive feedback is exploited to boost the equivalent transconductance of the first stage and the quasi-floating gate approach enables the...

The paper introduces a bulk-driven operational transconductance amplifier (OTA) suitable for ultra-low-power and ultra-low-voltage applications. The amplifier is made up of three gain stages and features inherent class-AB behavior and precise control of the quiescent current of all transistors. Additionally, positive feedback is exploited for the f...

In this paper the design of regulated active rectifiers (RARs) is addressed, with emphasis on energy harvesting applications. After an insightful overview of the main topologies of RARs, the analytical models are discussed and extended. Then, a data-driven comparison is carried out which, however, does not allows an absolute ranking between the dif...

The paper introduces an enhanced digital OTA topology which allows increasing the DC gain thanks to the adoption of an inverter-based output stage. Moreover, a new equivalent small-signal model is proposed which allows to simplify the circuit analysis and paves the way to new frequency compensation strategies. Designed using a 28-nm standard CMOS t...

This paper introduces a current reference based on $\Delta V_{GS}$ generation principle and adopts integrated poly-p+ resistors and a nW-power OTA to reduce the line sensitivity. Implemented in a 28-nm standard CMOS technology, the circuit provides a nominal current equal to 100nA and operates down to 0.6V with a line sensitivity equal to 1.2%/V...

In this brief an original scheme, exploiting the trans-conductive loop implemented through the bulk terminal of the PMOS transistors of cross-coupled charge pumps, is proposed to achieve the regulation of the output voltage of a charge pump. As compared to the conventional regulation schemes, the proposed one achieves wide regulation ranges in term...

A three-stage operational transconductance amplifier (OTA) stable for any load capacitor is introduced for the first time in literature. It contains a novel local ac feedback network in the intermediate stage in addition to the cascode-Miller compensation strategy. The final topology is Miller-compensated for the light and $C_{L}$ -compensated fo...

The paper describes a single-stage operational transconductance amplifier suitable for very-low-voltage operation in power-constrained applications. The proposed circuit avoids the tail current generator in the differential pair while preventing pseudo-differential operation. Moreover, the adoption of positive feedback allows increasing the stage t...

This paper introduces a design strategy for common-gate comparators, as the widely implemented comparators in active rectification systems. The method is based on the gm/ID technique and it embraces both the power conversion efficiency of the whole system and large signal performance parameters, such as the slew-rate. As an example, the proposed st...

Recently, with the aim of extending the use of the CP in all those applications where a time-variant signal must be amplified with its DC component above the positive power supply rail, the signal amplification feature of a conventional Dickson charge pump (CP) has been investigated, introducing a small-signal model for each particular condition in...

This paper proposes an optimal design approach for three-stage amplifiers driving an ultra-wide range of load capacitor. To this end, efficient state-of-the-art solutions have been combined to develop a power-efficient frequency compensation solution. High-speed feedback pathways relying on Miller capacitors and current buffers are implemented with...

Battery-less implantable medical devices (IMDs) are encountering an always growing interest in recent years. The ability to monitor body-organs activities using electrical stimulators requires the establishment of a Data Down-Link, while a Data Up-Link is an ubiquitous feature to monitor health conditions by acquiring biological signals. Under this...

An approach for the design of two-stage class-AB OTAs with sub- $1{\boldsymbol {\mu }}\text{A}$ current consumption is proposed and demonstrated. The approach employs MOS transistors operating in subthreshold and allows maximum gain-bandwidth product (GBW) to be achieved for a given DC current budget, by setting optimum distribution of DC currents...

In this paper it is proposed and explored the use of the Dickson charge pump (CP) to amplify time-variant signals. The study has been carried out through a theoretical analysis that provides an in-depth comprehension of the behavioral equations and the main design metrics commonly used to evaluate the performance of amplifiers. Starting from the an...

Low-invasive and battery-less implantable medical devices (IMDs) have been increasingly emerging in recent years. The developed solutions in the literature often concentrate on the Bidirectional Data-Link for long-term monitoring devices. Indeed, their ability to collect data and communicate them to the external world, namely Data Up-Link, has reve...

This paper presents a systematic analytical comparison of the single-Miller capacitor frequency compensation techniques suitable for three-stage complementary metal–oxide– semiconductor (CMOS) operational transconductance amplifiers (OTAs). The comparison is carried out with the aid of a figure of merit that expresses a trade-off among gain-bandwid...

In this paper, a simple while effective methodology to calculate the symbolic transfer function of a multistage amplifier with frequency compensation is proposed. Three general amplifier models are introduced and analyzed, which represent basic topologies found in the literature. For these amplifier models, the symbolic transfer function is derived...

This work proposes a Double Differential (DD) amplifier topology which exploits the advantages of the current-mode approach. DD amplifiers are useful as front-ends in standalone active electrodes for superficial electromyography (sEMG) wearable applications and electroneurography (ENG) measurement devices. Front-ends for these applications need to...

In this paper an advanced and accurate model of the Dickson Voltage Multiplier (DVM) accounting for charge-loss nonidealities, like reverse and substrate currents of the charge transfer devices, is proposed. Analytical equations for the single current loss and the various metrics are given. In particular, by inspection of the open-circuit output vo...

Charge-Based Capacitance Measurement (CBCM) technique is a simple but effective technique for measuring capacitance values down to the attofarad level. However, when adopted for fully on-chip implementation, this technique suffers output offset caused by mismatches and process variations. This paper introduces a novel method that compensates the of...

In this paper a brief tutorial of charge pump topologies for management of self-powered nodes in ultra-low-power applications, such as internet of things nodes, is presented. It aims to provide to the designer guidelines to choose the most suitable solution, according to the given design specifications. After a brief historic evolution, the main de...

Targeting the more recently adopted low-power memories for data-logging operation in IoT nodes, this paper presents a simple reconfigurable dual-branch cross-coupled charge pump (CP) topology in which clock amplitude scaling and modulation of the number of stages are exploited to improve power efficiency and/or change the output voltage without deg...

This paper aims to review the recent architectures of power management units for ultrasound-based energy harvesting, while focusing on battery-less implantable medical devices. In such systems, energy sustainability is based on piezoelectric devices and a power management circuit, which represents a key building block since it maximizes the power e...

This paper introduces the electronic interface for a capacitive airborne particle matter detector. The proposed circuit relies on two matched ring oscillators and a mixer to detect the frequency difference induced by the deposition of a particle onto an interdigitated capacitor, which constitutes the load of one of the oscillators. The output of th...

DC/DC converters are widely used in photovoltaic (PV) systems to track the maximum power points (MPP) of a photovoltaic generator (PVG). The variation of solar radiation (G) and PV cells temperature (T) affect the power efficiency of these DC/DC converters because they change the MPP, thus a sizing adaptation of the component values in these DC/DC...

In this article, a fully-integrated switched-capacitor DC-DC converter based on a Dickson charge pump able to work with input voltage levels that force the transistors working in subthreshold region is presented. The proposed topology exploits resistors in the charge transfer switch in order to overcome the limits of conventional solutions when wor...

Fully Depleted Silicon on Insulator (FD-SOI) CMOS technology offers the possibility of circuit performance optimization with reduction of both topology complexity and power consumption. These advantages are fully exploited in this paper in order to develop a new topology of active continuous-time second-order bandpass filter with maximum resonant f...

Capacitance detection is a universal transduction mechanism used in a wide variety of sensors and applications. It requires an electronic front-end converting the capacitance variation into another more convenient physical variable, ultimately determining the performance of the whole sensor. In this paper we present a comprehensive review of the di...

This letter introduces a novel scheme to improve charge transfer switches in linear charge pumps. The proposed approach relies on the reduction of the threshold voltage of the transistor implementing each charge transfer switch by forcing a current into its bulk junction. Simulation results using a 130‐nm standard complementary metal‐oxide semicond...

This paper proposes a comparative study of regulation schemes for charge-pump-based voltage generators using behavioral models in Verilog-Analog Mixed Signal (AMS) code. An accurate and simple model of the charge pump is first introduced. It allows reducing the simulation time of complex electronic systems made up by both analog and digital circuit...

In this paper a compact ultra-low power smart temperature sensor realized in 130-nm standard CMOS technology, provided by STMicroelectronics, is presented. The sensor is designed with the aim of measuring local temperature variations in the range of -20 °C to 85 °C in temperature drift compensation applications. It relies on a simple circuit topolo...

This work proposes a simple but effective strategy to improve wake-up operation in energy-autonomous systems which exploits Charge Pump (CP) circuits to boost voltage directly from energy harvester generators. By means of few auxiliary diodes and parasitic junctions, the CP is managed to retain the charges in the pumping capacitors when the harvest...

This paper introduces a design strategy to reduce rise time of charge pumps maintaining equal the silicon area, which is effective when the load capacitance is lower than the total charge pump capacitance. The strategy relies on an unconventional pumping capacitors sizing, which set them not equal and follows a linear distribution. The approach is...

Advanced multistage amplifiers suffer from load‐dependent stability issues, which limit the load capacitor range they can drive. In this work, the concept of global impedance attenuation (GIA) network is introduced to improve an amplifier's stability in the presence of significant load capacitor variations. Composed of multiple parallel resistor‐ca...

This paper introduces a simple design strategy to increase the power efficiency of linear charge pumps. The technique exploits a voltage amplitude of the clock signal lower than the supply voltage to reduce the power conversion losses. The nominal output voltage is maintained unaltered by increasing the number of stages.

The paper presents a novel charge pump suitable to work under very-low-voltage supply. The circuit exploits a novel charge transfer switch made up by the combination of a NMOS and a PMOS transistor whose gates are connected to internal nodes of the charge pump to enhance overdrive voltage. This solution allows working with supply voltage values low...

Nanometer CMOS technologies are characterized by low intrinsic gain and limited rejection to common‐mode disturbances, issues that analog designers must counteract through nonconventional circuit solutions able to operate under sub–1‐V supply voltages. In this letter, an approach originally proposed as a common‐mode control loop for body‐driven amp...

With the aim of providing designer guidelines for choosing the most suitable solution, according to the given design specifications, in this paper a review of charge pump (CP) topologies for the power management of Internet of Things (IoT) nodes is presented. Power management of IoT nodes represents a challenging task, especially when the output of...

In this paper an improved Dickson charge pump topology exploiting a clock boosting is presented. An accurate while simple theoretical model for the dynamic behavior of the charge pump is carried out. Analytical comparison with the traditional Dickson charge pump reveals that the proposed solution can achieve a rise time or area reduction between 10...

Smart homes/offices based on Wireless Sensor Networks (WSNs) can provide an assisted living and working environment to the users. In these applications, the distributed network nodes are made up of low-power low-cost high-energy-efficient electronic platforms equipped with sensors, microcontroller, radio and antenna, able to periodically sense, rec...

This paper introduces a Dickson charge pump topology using a clock boosting technique. Theoretical analysis of the rise time reveals that the proposed solution allows a reduction of the rise time for equal area occupation as compared to the conventional Dickson charge pump. Simulation results confirm the effectiveness of the proposed topology and t...

A power management integrated circuit for an energy autonomous device is presented. It is based on a configurable 2:1 switched capacitor converter capable of delivering a maximum current to always-on and duty-cycled loads equal to 5 A and 2 mA, respectively, from a thin-film 4.2-V lithium battery. The circuit is designed and implemented using the 0...

The main objectives of the present paper are to describe a pilot cogenerative PV/T plant and discuss its preliminary electrical and thermal experimental data. The PV/T plant is installed in the campus of the University of Catania, (Catania, Italy) on the eastern coast of Sicily, right in the centre of the Mediterranean area. The operative condition...

This paper presents the experimental validation of a low-power, large output swing, class-AB buffer amplifier for column drivers of active-matrix flatpanel displays. By exploiting two complementary input amplifiers and a dual-path push-pull output stage the proposed circuit achieves high-drive performance and rail-to-rail operation. In addition, tw...

This paper presents a low-power, area-efficient three-stage CMOS Operational Transconductance Amplifier (OTA) suitable for very large capacitive loads, CL. A single Miller capacitor and an inverting current buffer embedded in the input stage are exploited to implement the frequency compensation network. Additional feed-forward path and a slew rate...

This paper presents a trimming correction technique to calibrate the offset in capacitive readout circuits of MEMS sensors. The technique relies on a N-bit digital voltage divider which allows to implement an equivalent variable capacitor with sub-femto Farad step variations. To reduce area occupation, a hybrid approach entailing both resistive and...

This paper presents a CMOS operational transconductance amplifier (OTA), suitable for sub-1-V supply applications, whose (input) common-mode voltage can be set to (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DD</sub> + V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www....

In this paper, the traditional equivalent electrical model of silicon photomultipliers (SiPMs) is profitably extended to include the important effects of the read-out electronics on the shape of the output pulse waveforms. An improved analytical expression has been developed, which accurately reproduces the fast detector ignition, the avalanche sel...

This paper presents a power- and area-efficient three-stage amplifier suitable to drive high capacitive loads. The amplifier is compensated by a single Miller Capacitor and an additional feedforward stage. To improve the amplifier large signal transient response, the topology also includes an external feedforward path and a novel slew-rate enhancer...

La coppia differenziale è uno dei blocchi elementari più importanti nella realizzazione di circuiti integrati; su essa sono basati sottosistemi fondamentali quali amplificatori, moltiplicatori, mixer, transconduttori, filtri, ecc. In questo lavoro si è studiata una soluzione operante a bassissima tensione di alimentazione (<1V) per applicazioni low...

This paper introduces a new effective single-Miller capacitor compensation topology for three-stage amplifiers with very large capacitive loads, realized through an active-feedback capacitor together with an inner half-feedforward stage. Moreover, an optimized design strategy which profitably exploits the two left half-plane zeros is presented. To...

The noise of cascode transistors is usually considered to be negligible. It is demonstrated in this paper that this is not the case for an operational transconductance amplifiers exploiting Miller compensation via an embedded current buffer. Analysis, validated through simulations, shows that the noise power spectral density of the cascode transist...

A simple high-performance architecture for bulk-driven operational transconductance amplifiers (OTAs) is presented. The solution, suitable for operation under sub 1-V single supply, is made up of three gain stages and, as an additional feature, provides inherent class-AB behavior with accurate and robust standby current control. The OTA is fabricat...

A compensation technique for low-power three-stage operational transconductance amplifiers is presented in this paper. The compensation network is made up of passive components and entails only one Miller capacitor. Design equations describing the amplifier behavior for different capacitive load conditions are reported along with three design examp...

An ultra-low-power high-performance three-stage subthreshold CMOS OTA is presented together with its detailed design methodology. The amplifier is realized in a 0.35-μm technology, is powered from a 1-V supply, exhibits 120-dB DC gain and is designed to drive a capacitive load up to 200 pF. Despite the allowed heavy load, it occupies only 4.4–10−3...