416 research outputs found
Utilizing Unconventional CMOS Techniques for Low Voltage Low Power Analog Circuits Design for Biomedical Applications
Tato disertaÄnĂ prĂĄce se zabĂœvĂĄ navrĆŸenĂm nĂzkonapÄĆ„ovĂœch, nĂzkopĆĂkonovĂœch analogovĂœch obvodĆŻ, kterĂ© pouĆŸĂvajĂ nekonvenÄnĂ techniky CMOS. LĂ©kaĆskĂĄ zaĆĂzenĂ na bateriovĂ© napĂĄjenĂ, jako systĂ©my pro dlouhodobĂœ fyziologickĂœ monitoring, pĆenosnĂ© systĂ©my, implantovatelnĂ© systĂ©my a systĂ©my vhodnĂ© na noĆĄenĂ, musĂ bĂœt male a lehkĂ©. KromÄ toho je nutnĂ©, aby byly tyto systĂ©my vybaveny bateriĂ s dlouhou ĆŸivotnostĂ. Z tohoto dĆŻvodu pĆevlĂĄdajĂ v biomedicĂnskĂœch aplikacĂch tohoto typu nĂzkopĆĂkonovĂ© integrovanĂ© obvody. NekonvenÄnĂ techniky jako napĆ. vyuĆŸitĂ transistorĆŻ s ĆĂzenĂœm substrĂĄtem (Bulk-Driven âBDâ), s plovoucĂm hradlem (Floating-Gate âFGâ), s kvazi plovoucĂm hradlem (Quasi-Floating-Gate âQFGâ), s ĆĂzenĂœm substrĂĄtem s plovoucĂm hradlem (Bulk-Driven Floating-Gate âBD-FGâ) a s ĆĂzenĂœm substrĂĄtem s kvazi plovoucĂm hradlem (Bulk-Driven Quasi-Floating-Gate âBD-QFGâ), se v nedĂĄvnĂ© dobÄ ukĂĄzaly jako efektivnĂ prostĆedek ke zjednoduĆĄenĂ obvodovĂ©ho zapojenĂ a ke snĂĆŸenĂ velikosti napĂĄjecĂho napÄtĂ smÄrem k prahovĂ©mu napÄtĂ u tranzistorĆŻ MOS (MOST). V prĂĄci jsou podrobnÄ pĆedstaveny nejdĆŻleĆŸitÄjĆĄĂ charakteristiky nekonvenÄnĂch technik CMOS. Tyto techniky byly pouĆŸity pro vytvoĆenĂ nĂzko napÄĆ„ovĂœch a nĂzko vĂœkonovĂœch CMOS struktur u nÄkterĂœch aktivnĂch prvkĆŻ, napĆ. Operational Transconductance Amplifier (OTA) zaloĆŸenĂ© na BD, FG, QFG, a BD-QFG techniky; Tunable Transconductor zaloĆŸenĂœ na BD MOST; Current Conveyor Transconductance Amplifier (CCTA) zaloĆŸenĂœ na BD-QFG MOST; Z Copy-Current Controlled-Current Differencing Buffered Amplifier (ZC-CC-CDBA) zaloĆŸenĂœ na BD MOST; Winner Take All (WTA) and Loser Take All (LTA) zaloĆŸenĂœ na BD MOST; Fully Balanced Four-Terminal Floating Nullor (FBFTFN) zaloĆŸenĂœ na BD-QFG technice. Za ĂșÄelem ovÄĆenĂ funkÄnosti vĂœĆĄe zmĂnÄnĂœch struktur, byly tyto struktury pouĆŸity v nÄkolika aplikacĂch. VĂœkon navrĆŸenĂœch aktivnĂch prvkĆŻ a pĆĂkladech aplikacĂ je ovÄĆovĂĄn prostĆednictvĂm simulaÄnĂch programĆŻ PSpice Äi Cadence za pouĆŸitĂ technologie 0.18 m CMOS.This doctoral thesis deals with designing ultra-low-voltage (LV) low-power (LP) analog circuits utilizing the unconventional CMOS techniques. Battery powered medical devices such as; long term physiological monitoring, portable, implantable, and wearable systems need to be small and lightweight. Besides, long life battery is essential need for these devices. Thus, low-power integrated circuits are always paramount in such biomedical applications. Recently, unconventional CMOS techniques i.e. Bulk-Driven (BD), Floating-Gate (FG), Quasi-Floating-Gate (QFG), Bulk-Driven Floating-Gate (BD-FG) and Bulk-Driven Quasi-Floating-Gate (BD-QFG) MOS transistors (MOSTs) have revealed as effective devices to reduce the circuit complexity and push the voltage supply of the circuit towards threshold voltage of the MOST. In this work, the most important features of the unconventional CMOS techniques are discussed in details. These techniques have been utilized to perform ultra-LV LP CMOS structures of several active elements i.e. Operational Transconductance Amplifier (OTA) based on BD, FG, QFG, and BD-QFG techniques; Tunable Transconductor based on BD MOST; Current Conveyor Transconductance Amplifier (CCTA) based on BD-QFG MOST; Z Copy-Current Controlled-Current Differencing Buffered Amplifier (ZC-CC-CDBA) based on BD MOST; Winner Take All (WTA) and Loser Take All (LTA) based on BD MOST; Fully Balanced Four-Terminal Floating Nullor (FBFTFN) based on BD-QFG technique. Moreover, to verify the workability of the proposed structures, they were employed in several applications. The performance of the proposed active elements and their applications were investigated through PSpice or Cadence simulation program using 0.18 m CMOS technology.
Low Voltage Low Power Analogue Circuits Design
DisertaÄnĂ prĂĄce je zamÄĆena na vĂœzkum nejbÄĆŸnÄjĆĄĂch metod, kterĂ© se vyuĆŸĂvajĂ pĆi nĂĄvrhu analogovĂœch obvodĆŻ s vyuĆŸitĂ nĂzkonapÄĆ„ovĂœch (LV) a nĂzkopĆĂkonovĂœch (LP) struktur. Tyto LV LP obvody mohou bĂœt vytvoĆeny dĂky vyspÄlĂœm technologiĂm nebo takĂ© vyuĆŸitĂm pokroÄilĂœch technik nĂĄvrhu. DisertaÄnĂ prĂĄce se zabĂœvĂĄ prĂĄvÄ pokroÄilĂœmi technikami nĂĄvrhu, pĆedevĆĄĂm pak nekonvenÄnĂmi. Mezi tyto techniky patĆĂ vyuĆŸitĂ prvkĆŻ s ĆĂzenĂœm substrĂĄtem (bulk-driven - BD), s plovoucĂm hradlem (floating-gate - FG), s kvazi plovoucĂm hradlem (quasi-floating-gate - QFG), s ĆĂzenĂœm substrĂĄtem s plovoucĂm hradlem (bulk-driven floating-gate - BD-FG) a s ĆĂzenĂœm substrĂĄtem s kvazi plovoucĂm hradlem (quasi-floating-gate - BD-QFG). PrĂĄce je takĂ© orientovĂĄna na moĆŸnĂ© zpĆŻsoby implementace znĂĄmĂœch a modernĂch aktivnĂch prvkĆŻ pracujĂcĂch v napÄĆ„ovĂ©m, proudovĂ©m nebo mix-mĂłdu. Mezi tyto prvky lze zaÄlenit zesilovaÄe typu OTA (operational transconductance amplifier), CCII (second generation current conveyor), FB-CCII (fully-differential second generation current conveyor), FB-DDA (fully-balanced differential difference amplifier), VDTA (voltage differencing transconductance amplifier), CC-CDBA (current-controlled current differencing buffered amplifier) a CFOA (current feedback operational amplifier). Za ĂșÄelem potvrzenĂ funkÄnosti a chovĂĄnĂ vĂœĆĄe zmĂnÄnĂœch struktur a prvkĆŻ byly vytvoĆeny pĆĂklady aplikacĂ, kterĂ© simulujĂ usmÄrĆovacĂ a induktanÄnĂ vlastnosti diody, dĂĄle pak filtry dolnĂ propusti, pĂĄsmovĂ© propusti a takĂ© univerzĂĄlnĂ filtry. VĆĄechny aktivnĂ prvky a pĆĂklady aplikacĂ byly ovÄĆeny pomocĂ PSpice simulacĂ s vyuĆŸitĂm parametrĆŻ technologie 0,18 m TSMC CMOS. Pro ilustraci pĆesnĂ©ho a ĂșÄinnĂ©ho chovĂĄnĂ struktur je v disertaÄnĂ prĂĄci zahrnuto velkĂ© mnoĆŸstvĂ simulaÄnĂch vĂœsledkĆŻ.The dissertation thesis is aiming at examining the most common methods adopted by analog circuits' designers in order to achieve low voltage (LV) low power (LP) configurations. The capability of LV LP operation could be achieved either by developed technologies or by design techniques. The thesis is concentrating upon design techniques, especially the nonâconventional ones which are bulkâdriven (BD), floatingâgate (FG), quasiâfloatingâgate (QFG), bulkâdriven floatingâgate (BDâFG) and bulkâdriven quasiâfloatingâgate (BDâQFG) techniques. The thesis also looks at ways of implementing structures of wellâknown and modern active elements operating in voltageâ, currentâ, and mixedâmode such as operational transconductance amplifier (OTA), second generation current conveyor (CCII), fullyâdifferential second generation current conveyor (FBâCCII), fullyâbalanced differential difference amplifier (FBâDDA), voltage differencing transconductance amplifier (VDTA), currentâcontrolled current differencing buffered amplifier (CCâCDBA) and current feedback operational amplifier (CFOA). In order to confirm the functionality and behavior of these configurations and elements, they have been utilized in application examples such as diodeâless rectifier and inductance simulations, as well as lowâpass, bandâpass and universal filters. All active elements and application examples have been verified by PSpice simulator using the 0.18 m TSMC CMOS parameters. Sufficient numbers of simulated plots are included in this thesis to illustrate the precise and strong behavior of structures.
Ultra low power circuits for a miniature apnoea detection device
Imperial Users onl
CMOS design of chaotic oscillators using state variables: a monolithic Chua's circuit
This paper presents design considerations for monolithic implementation of piecewise-linear (PWL) dynamic systems in CMOS technology. Starting from a review of available CMOS circuit primitives and their respective merits and drawbacks, the paper proposes a synthesis approach for PWL dynamic systems, based on state-variable methods, and identifies the associated analog operators. The GmC approach, combining quasi-linear VCCS's, PWL VCCS's, and capacitors is then explored regarding the implementation of these operators. CMOS basic building blocks for the realization of the quasi-linear VCCS's and PWL VCCS's are presented and applied to design a Chua's circuit IC. The influence of GmC parasitics on the performance of dynamic PWL systems is illustrated through this example. Measured chaotic attractors from a Chua's circuit prototype are given. The prototype has been fabricated in a 2.4- mu m double-poly n-well CMOS technology, and occupies 0.35 mm/sup 2/, with a power consumption of 1.6 mW for a +or-2.5-V symmetric supply. Measurements show bifurcation toward a double-scroll Chua's attractor by changing a bias current
Design of Analog CMOS Circuits for Batteryless Implantable Telemetry Systems
A wireless biomedical telemetry system is a device that collects biomedical signal measurements and transmits data through wireless RF communication. Testing medical treatments often involves experimentation on small laboratory animals, such as genetically modified mice and rats. Using batteries as a power source results in many practical issues, such as increased size of the implant and limited operating lifetime. Wireless power harvesting for implantable biomedical devices removes the need for batteries integrated into the implant. This will reduce device size and remove the need for surgical replacement due to battery depletion. Resonant inductive coupling achieves wireless power transfer in a manner modelled by a step down transformer. With this methodology, power harvesting for an implantable device is realized with the use of a large primary coil external to the subject, and a smaller secondary coil integrated into the implant. The signal received from the secondary coil must be regulated to provide a stable direct current (DC) power supply, which will be used to power the electronics in the implantable device. The focus of this work is on development of an electronic front-end for wireless powering of an implantable biomedical device. The energy harvesting front-end circuit is comprised of a rectifier, LDO regulator, and a temperature insensitive voltage reference. Physical design of the front-end circuit is developed in 0.13um CMOS technology with careful attention to analog layout issues. Post-layout simulation results are presented for each sub-block as well as the full front-end structure. The LDO regulator operates with supply voltages in the range of 1V to 1.5V with quiescent current of 10.5uA The complete power receiver front-end has a power conversion efficiency of up to 29%
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A CMOS Magnitude/Phase Measurement Chip for Impedance Spectroscopy
The measurement of electrical impedance is used in a plethora of biomedical applications. The most common technique used is synchronous demodulation, which provides the real and imaginary parts of the impedance. However, in practice, the method requires elaborate calibration and matching between the injection and monitoring stages. This paper presents the integrated realization of an alternative method that is less intricate to implement. The circuit was fabricated in a 0.35-Όm CMOS technology, occupies an active area of 0.4 mm2 , and dissipates about 21 mW of power from ±2.5 V supplies. The chip was used to measure equivalent RC circuits of the electrode-tissue interface over the frequency range of 100 Hz to 100 kHz, showing good correlation with the theoretical results
Tehonhallinta integroidulle hermosignaalin hallintapiirille
Wireless biosignal measurement is a growing opportunity to increase the efficiency of medical procedures: An integrated circuit (receiver) is implanted inside human tissue and itâs output can be read wirelessly with a transmitter that also provides energy for the implant. This method requires RFID technology, where wireless data is transmitted in the RF-band back-and-forth between the receiver and transmitter.
The receiver can be implemented either as an active design, where a local power supply is required inside the receiver, or as a passive design without internal energy storage. However, as the modern CMOS process is fairly advanced and the power consumption is low - passive designs are the most common.
In the passive design the power for the receiver is drawn from the electromagnetic field transmitted to the chip, generally with electromagnetic induction. A design and implementation of an 860 MHz UHF-band RFID power system is presented in this work and its performance evaluated. The system was designed for a wireless EEG (electroencephalography) reader that can be implanted under the skalp â but the design principles can be expanded upon any RF-band RFID system.
The final system works with an input power of -6.8 dBm with a startup time of slightly below 40 ”s with specifications of 700 mV to 150 ”A load. The LDO line regulation achieves a -51 dB level at DC with the full bandwidth covered. The RF Rectifier uses the design principles of a cross-coupled rectifier and a 63% conversion efficiency is achieved with the proposed matching circuitry. The reference circuitry is designed with the Betamultiplier architecture and expanded slightly to improve the current consumption in the circuit. The reference current is set at 100 nA and reference voltage at 400 mV.Langaton biosignaalien mittaus mahdollistaa yleisien lÀÀketieteellisien signaalien mittauksien tehokkuuden kasvamista: Integroitu elektroninen piiri voidaan asentaa ihmisen kudokseen ja tÀmÀn sirun ulosantama tieto voidaan lukea langattomasti lukijalla, mikÀ useassa tapauksessa toimittaa myös energian sirulle. TÀmÀ teknologia vaatii RFID teknologiaa, mikÀ on hyvin tunnettu ja tutkittu langattoman datan siirtÀmiseen kehitelty teknologia radiotaajuuksilla lukijan ja vastaanottimen vÀlillÀ.
Lukija voidaan suunnitella sekÀ passiiviseksi ettÀ aktiiviseksi, mutta modernin CMOS- teknologian tehonkulutus ominaisuuksien vuoksi RFID-lukijat ovat yleisesti passiivisia.
Passiivisessa RFID suunnittelussa lukija vastaanottaa tarvitsemansa energian vastaanottimelta yleisesti elektromagneettisen induktion avulla. 860 MHz UHF-kaistan suunnitelu ja toteutus kÀydÀÀn lÀpi tÀssÀ työssÀ ja suorityskyky on mitattu simulaatioilla. Itse jÀrjestelmÀ oli alunperin suunniteltu langattomaan EEG-lukijaan (aivosÀhkökÀyrÀ), minkÀ pystyisi asentamaan pÀÀnahan alle - mutta periaatteet pÀtevÀt mihin tahansa RF-kaistan jÀrjestelmÀÀn.
Lopullinen jÀrjestelmÀ toimii -6.8 dBm sisÀÀntuloteholla ja kÀynnistysmisaika on hieman alle 40”s 700 mV ja 150 ”A kuormaan. Linjaregulaatio saavuttaa -51 dB arvon alhaisilla taajuuksilla ja regulaatio on koko kaistan kattava. RF-tasasuuntaaja saavuttaa 63 % AC-DC huippu tehonmuutosarvon ehdotetulla impedanssien sovituspiirillÀ. Referenssipiiri on suunnitellu Betamultiplier-arkkitehtuurilla ja modifioitu pienentÀmÀÀn virrankulutusta. Referenssit ovat 100 nA ja 400 mV
Design and Assembly of High-Temperature Signal Conditioning System on LTCC with Silicon Carbide CMOS Circuits
The objective of the work described in this dissertation paper is to develop a prototype electronic module on a low-temperature co-fired ceramic (LTCC) material. The electronic module would perform signal conditioning of sensor signals (thermocouples) operating under extreme conditions for applications like gas turbines to collect data on the health of the turbine blades during operation so that the turbines do not require shutdown for inspection to determine if maintenance is required. The collected data can indicate when such shutdowns, which cost $1M per day, should be scheduled and maintenance actually performed. The circuits for the signal conditioning system within the prototype module must survive the extreme temperature, pressure, and centrifugal force, or G-force, present in these settings. Multiple fabrication runs on different integrated silicon carbide (SiC) process technologies have been carried out to meet the system requirements. The key circuits described in this dissertation are - two-stage op amp topologies and voltage reference, which are designed and fabricated in a new SiC CMOS process. The SiC two-stage op amp with PFET differential input pair showed 48.9 dB of DC gain at 500oC. The voltage reference is the first in SiC CMOS technology to employ an op amp-based topology. The op amp circuit in the voltage reference is a two-stage with NFET differential input pair that uses the indirect compensation technique for the first time in the SiC CMOS process to provide 42.5 dB gain at 350oC. The designed prototype module implemented with these circuits was verified to provide signal conditioning and signal transmission at 300oC. The signal transmission circuit on the module was also verified to operate with a resonant inductive wireless power transfer method at a frequency of 11.8 MHz for the first time. A second prototype module was also developed with the previously fabricated 1.2 ”m SiC CMOS process. The second module was successfully tested (with wired power supply) to operate at 440oC inside a probe-station and also verified for the first time to sustain signal transmission (34.65 MHz) capability inside a spin-rig at a rotational speed of 10,920 rpm. All designed modules have dimensions of (length) 68.5 mm by (width) 34.3 mm to conform to the physical size requirements of the gas turbine blade
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