Showing papers on "Relaxation oscillator published in 2011"

A novel current conveyor-based Schmitt trigger and its application as a relaxation oscillator

Abstract: The current paper presents a novel Schmitt trigger using two second-generation current conveyors and four resistors and its application as a relaxation oscillator. The performance of the proposed circuit is examined using Cadence and the model parameters of a 0.6µm CMOS process. The obtained results demonstrate excellent agreement with the theoretical values. The measured results based on commercially available current feedback operational amplifiers (AD 844 AN) are included and the non-idealities are also examined. The topology reports low sensitivities and has features suitable for VLSI implementation. Copyright © 2010 John Wiley & Sons, Ltd. (The current paper presents a novel Schmitt trigger using two second-generation current conveyors and four resistors and its application as a relaxation oscillator. The performance of the proposed circuit is examined using Cadence and the model parameters of a 0.6 m CMOS process. The obtained results demonstrate excellent agreement with the theoretical values.)

Fully and electronically controllable current-mode Schmitt triggers employing only single MO-CCCDTA and their applications

Abstract: This article presents the new current-mode counterclockwise (CCW) and clockwise (CW) Schmitt triggers based on multiple-output current controlled current differencing transconductance amplifier (MO-CCCDTA). The circuit descriptions are very simple, each construction consists of only single MO-CCCDTA, without any external passive element. The hysteresis and amplitude of the output current of each Schmitt trigger can be tuned independently/electronically by input bias currents. In addition, the output signals are independent of the thermal voltage (VT). The applications as a relaxation oscillator, triangular/square wave generator, pulse width modulation and monostable multivibrator are given here to display the usefulnesses of the presented Schmitt triggers. The PSpice simulation and experimental results are depicted, and agree well with the theoretical anticipation. The maximum power consumptions of CCW and CW Schmitt triggers are approximately 235 and 191 μW, respectively, at ±1.5 V supply voltages.

Phase-Noise Reduction in Oscillators via Small-Signal Injection

Abstract: This paper provides an original investigation around the phenomenon of phase-noise reduction in oscillators due to small-signal injection. The analysis employs phase-domain macromodeling techniques and fundamental results from the theory of stochastic processes. The proposed analysis also applies to strongly nonlinear circuits such as ring or relaxation oscillators, and relies on quantities which are easily measurable or derivable by designers.

Atomic clock reference frequency obtaining method and atomic clock

Abstract: The invention discloses an obtaining method of atomic clock reference frequency and atomic clock thereof. The method includes the following steps: a semiconductor laser is driven by a drive current source, and the semiconductor laser is modulated by microwave signals simultaneously; two pumping lasers with same frequency difference and modulating frequency of microwave signals can be generated; the two pumping lasers act on atoms having an Lambda three-level system; when the frequency of microwave signals has deviation with the interval of two lower levels of the Lambda three-level system of the atoms and when the frequency deviation is bigger than spectral half width of coherent population tripping (CPT), a relaxation oscillator signal with the same frequency as CPT detuning transient oscillation is generated; and the frequency of the relaxation oscillator signal is added with the modulating frequency of the microwave signals so as to obtain standard frequency of an atomic clock. Theatomic clock designed according to the method has simple structure and omits a locking circuit of the traditional atomic clock, thereby improving the adaptability for the external environment.

A low-power dual-modulus injection-locked frequency divider for medical implants

Abstract: In this paper, we propose a low-power dual-modulus injection-locked frequency divider (ILFD) based on a relaxation oscillator, which is shown to be suitable for injection-locked frequency divider design. By varying the center frequency based on the modulus control bit, the divider can achieve different division ratios. For validation, two dual-modulus ILFDs which can achieve different division ratios such 2/3, 3/4, 4/5 are simulated in a 90 nm CMOS process technology with two tuning methods. The divider covers the frequency range of the medical implant communications service (MICS) and the industrial, scientific and medical (ISM) frequency bands for low power applications.

Relaxation oscillator with low power consumption

Abstract: A relaxation oscillator for generating oscillator signal includes a ramp voltage generating circuit, a reference voltage generating circuit, a reference voltage switching circuit, and a digital logic circuit. The reference voltage generating circuit generates one or more reference voltages and the ramp voltage generating circuit generates one or more ramp voltages. The ramp voltages are compared with each of the reference voltages by sequentially switching the reference voltages using a reference voltage switching signal generated by the reference voltage switching circuit. The oscillator signal is generated by the digital logic circuit based on the results of the comparisons.

Relaxation oscillator having a supply voltage independent output frequency

Abstract: Techniques and architectures corresponding to relaxation oscillators having output frequencies that are supply voltage independent are described. In a particular embodiment, an apparatus includes a relaxation oscillator having one or more capacitors and a compensation current circuit coupled to the relaxation oscillator. The compensation current circuit is configured to regulate current provided to the one or more capacitors of the relaxation oscillator in response to changes in a supply voltage provided to the compensation current circuit and to the relaxation oscillator.

A low-power referenceless clock and data recovery circuit with clock-edge modulation for biomedical sensor applications

Abstract: This paper proposes a low-power referenceless clock and data recovery (CDR) circuit for biomedical devices or sensor applications. Its power consumption is reduced by adopting clock-edge modulation technique and using a voltage-controlled oscillator (VCO) based on a relaxation oscillator. Clock-edge modulation eliminates the need for an external reference clock without introducing the possibility of harmonic locking. Our CDR supports input data-rates between 200kbps and 10Mbps at 0.7V, and operate up to 24 MHz at 1.0V. The circuit is designed in a 0.18μm CMOS technology and consumes 8μW at an input data-rate of 10Mbps.

A Fully Integrated and Reconfigurable Architecture for Coherent Self-Testing of High Speed Analog-to-Digital Converters

Abstract: This paper presents a reconfigurable architecture for coherent built-in self-testing (BIST) of high speed analog-to-digital converters (ADCs) with moderate resolutions. The proposed system is suited to be fully integrated with the ADC and, besides a low jitter clock reference, no other external high quality generators are required. The complete system comprises two synchronized phase-locked loops (PLLs), one based on a two-integrator oscillator capable of providing low distortion outputs and another based on a relaxation oscillator providing low jitter squared output, to allow coherent sampling. A detailed description of the building blocks of both PLLs is given as well as the techniques used to minimize area of the loop filters (LFs), to stabilize the output amplitude of the two-integrator oscillator to a known value, and to improve the total harmonic distortion (THD) of this oscillator. Post-layout simulations, in a 0.13 μm CMOS technology, of the proposed BIST scheme applied to a case-study 6-bit 1 GS/s ADC are shown and validate the proposed test methodology.

A 1 mW low phase-noise relaxation oscillator

Abstract: We present a new RC relaxation oscillator with pulse self biasing, to reduce power consumption, and with harmonic filtering and resistor feedback, to reduce phase-noise. A circuit prototype in the hundreds of MHz range, designed in a 130 nm CMOS technology has a very low phase-noise, −132.6 dBc/Hz @ 10 MHz offset, and the power consumption is only 1 mW, which leads to a figure of merit (FOM) of −159.1 dBc/Hz.

Scaling of Silicon Phase-Change Oscillators

Abstract: Scalability of silicon-based phase-change oscillators is investigated through experimental and computational studies. These relaxation oscillators are composed of a small volume of silicon, dc biased through a load resistor and a capacitor, which melts due to self-heating and resolidifies upon discharge of the load capacitor. These phase changes lead to high-amplitude current spikes with oscillation frequency that scales with supply voltage, RC time constant, power delivery condition, and heating and cooling rates of the wire. Experimental results are obtained from structures fabricated using silicon-on-insulator substrates. Scaling effects of various parameters are explored using 3-D finite-element simulations coupled with SPICE models.

Gm-C filter tuning circuit based on relaxation oscillator

Abstract: A relaxation oscillator for generating a first and a second oscillation signals, comprising: a reference-voltage providing circuit for providing a high and a low reference voltages; switches for directing the high and low reference voltages to inputs of a transconductance amplifier and a non-inverting input of a comparator; the transconductance amplifier for generating an output current with a value determined by its transconductance value, controlled by an input tuning voltage, and multiplied by its inputs' voltage difference; a capacitor connecting between the transconductance amplifier output and ground; and the comparator for generating a first and a second digital signals; wherein the first and second digital signals are digital control signals to the switches, and the first and second oscillation signal of the relaxation oscillator respectively; wherein the oscillation frequency of the relaxation oscillator is independent of the reference voltages, achieving accurate frequency turning, and simplifying the reference-voltage providing circuit.

Application of the double relaxation oscillation superconducting quantum interference device sensor to micro-tesla 1H nuclear magnetic resonance experiments

Abstract: We developed an ultra-low field (ULF)-nuclear magnetic resonance (NMR) measurement system capable of working with a measurement field (Bm) of several micro-tesla and performed basic NMR studies with a double relaxation oscillation superconducting quantum interference device (DROS) instead of conventional dc-SQUIDs. DROS is a SQUID sensor utilizing a relaxation oscillation between a dc-SQUID and a relaxation circuit; the new unit consists of an inductor and a resistor, and is connected in parallel with the SQUID. DROS has a 10 times larger flux-to-voltage transfer coefficient (∼mV/ϕ0) than that of the dc-SQUID, and this large transfer coefficient enables the acquisition of the SQUID signal with a simple flux-locked-loop (FLL) circuit using room temperature pre-amplifiers. The DROS second-order gradiometer showed average field noise of 9.2 μϕ0/√Hz in a magnetically shielded room (MSR). In addition, a current limiter formed of a Josephson junction array was put in a flux-transformer of DROS to prevent excess...

A new CMOS astable multivibrator and its nonlinear analysis

Abstract: We present a nonlinear analysis of a new inductively tuned astable multivibrator obtained by connecting a timing inductor across a composite nonlinear resistor with a characteristic of N-type, which is made up of the parallel connection of two complementary pairs of cross-coupled MOS devices Some possible practical applications of the circuit are also envisaged Closed-form expressions for the amplitude and the period of the periodic oscillation are derived in both cases when the circuit exhibits a relaxation oscillation and in the more difficult case when, due to the effect of parasitic capacitances of the devices, the circuit has an almost-discontinuous relaxation oscillation with a nonzero switching time The accuracy of the presented formulas, which are useful for both the analysis and design, is validated through circuit simulations and experimental results Copyright © 2009 John Wiley & Sons, Ltd

Periodic orbits in glycolytic oscillators: From elliptic orbits to relaxation oscillations

Abstract: We consider the Sel’kov model of glycolytic oscillator for a quantitative study of the limit cycle oscillations in the system. We identify a region of parameter space where perturbation theory holds and use both Linstedt Poincare technique and harmonic balance to obtain the shape and frequency of the limit cycle. The agreement with the numerically obtained result is excellent. We also find a different extreme, where the limit cycle is of the relaxation oscillator variety, has a large time period and it is seen that, as a particular parameter in the model is varied, the time period increases indefinitely. We characterize this divergence numerically. A calculational method is devised to capture the divergence approximately.

A linear, ultra wideband, low-power, 2.1–5 GHz, VCO

Abstract: A linear, Ultra Wideband, low-power VCO, suitable for UWB-FM applications is proposed, forming the main part of a UWB-FM transmitter. The VCO is designed in TSMC 90thinspacenm digital CMOS process and includes a Source-Coupled Multivibrator, used as current-controlled oscillator (CCO) which generates output frequencies between 2.1 and 5 GHz and a voltage-to-current (V-to-I) converter which translates the VCO input voltage modulation signal to current. Two single-ended inverter buffers are employed to drive either a differential or a single-ended UWB antenna. The presented VCO is designed for 1 V power supply and exhibits a linear tuning range of 2.1–5 GHz, a differential output power of −7.83 dBm±0.78 dB and low power consumption of 8.26 mW, including the output buffers, at the maximum oscillation frequency. It is optimized for a very high ratio of tuning range (81.69%) over power consumption equal to 9.95 dB. The desired frequency band of 3.1–5 GHz for UWB-FM applications is covered for the entire industrial temperature range (−40 to 125∘C). Copyright © 2010 John Wiley & Sons, Ltd.

Versatile voltage controlled relaxation oscillators using OTRA

Abstract: In this paper Operational Trans-Resistance Amplifier (OTRA) based voltage controlled oscillators are presented. They have a low component count and are easy to realize. The sensitivity (Hz per Volts) and tuning range can be configured just by controlling the value of the resistors. The oscillator circuit is insensitive to parasitic input capacitances and input resistances due to internally grounded input terminals of OTRA. PSpice simulations are given to verify the theoretical analysis.

Non-ideal behavior of a comparator-based relaxation oscillator

Abstract: The non-ideal behaviour of a classical comparator-based first-order relaxation oscillator is analysed. The influences of the comparator slew-rate and output resistance as well as the parasitic resistances of the reactive element are considered. Numerical simulations at system level and transistor level are given.

Ultra-Wideband, Low-Power, Inductorless, 3.1–4.8 GHz, CMOS VCO

Abstract: A low-power, inductorless, UWB CMOS voltage controlled oscillator is designed in 0.18 μm CMOS technology targeting to a UWBFM transmitter application. The VCO is a Double-Cross-Coupled Multivibrator and generates output frequencies ranging from 1.55 GHz to 2.4 GHz. A low-power frequency doubler based on a Gilbert cell, which operates in weak inversion, doubles the VCO tuning range from 3.1 GHz to 4.8 GHz. The proportionality between the oscillation frequency and the bias current is avoided in this case for the entire achieved tuning range resulting in a low-power design. The selected architecture provides high suppression, over 45 dB, for the 1st and 3rd harmonics, while enabling high-frequency operation and conversion gain due to the unbalanced structure and the single-ended output. The proposed VCO draws 4 mA from a 1.8 V supply, it has a phase noise of −76.7 dBc/Hz at 1 MHz offset from the center frequency, while it exhibits a very high ratio of tuning range (43%) over power consumption equal to 7.76 dB.

A relaxation oscillator with multi-phase triangular waveform generation

Abstract: This paper firstly presents a CMOS voltage-controlled oscillator (VCO) which enables octa-phase triangular waveform generation. By utilizing a cascaded relaxation oscillator core followed by a pseudo injection-locked oscillator circuit, an octa-phase differential VCO with triangular waveform outputs is realized. Simulation results show that the proposed fully differential multi-phase VCO can achieve broad tuning range with programmable timing capacitors, offering <1% phase mismatch.

A pseudo differential G m —C complex filter with frequency tuning for IEEE802.15.4 applications

Abstract: This paper presents a CMOS Gm—C complex filter for a low-IF receiver of the IEEE 802.15.4 standard. A pseudo differential OTA with reconfigurable common mode feedback and common mode feed-forward is proposed as well as the frequency tuning method based on a relaxation oscillator. A detailed analysis of non-ideality of the OTA and the frequency tuning method is elaborated. The analysis and measurement results have shown that the center frequency of the complex filter could be tuned accurately. The chip was fabricated in a standard 0.35 μm CMOS process, with a single 3.3 V power supply. The filter consumes 2.1mA current, has a measured in-band group delay ripple of less than 0.16 μs and an IRR larger than 28 dB at 2 MHz apart, which could meet the requirements oftheIEEE802.15.4 standard.

Simple portable storage battery charger for direct current panel

Abstract: The utility model relates to a storage battery charger, in particular to a simple portable storage battery charger for a direct current panel, which adopts the technical scheme that a diode, a resistor, an LED, a switch, a protective tube, controllable silicon and a relaxation oscillator are included, wherein the diode, the resistor, the LED, the switch and the protective tube are switched into an AC power supply after being connected in series, and the resistor and the relaxation oscillator as well as a voltage stabilizing pipe and the relaxation oscillator are switched into a 220 V AC power supply after being connected in series and in parallel respectively; the anode of the controllable silicon is connected with an amperemeter in series and then is connected to the negative terminal of a battery to be charged, and the positive terminal of the battery to be charged is connected to a commercial power neutral wire, and the LED serves as charging indication. The utility model has the benefits that the charging voltage can be continuously adjusted within 0 to 50 V, the current can be continuously adjusted within 0 to 10 A, and since a supply transformer is not included, the circuit is simple, light, small in volume and low in cost, the maximum power can reach 500 W, and the storage battery charger can charge a plurality of storage batteries at the same time, and has certain depolarization function.

Device and method for generating a signal of parametrizable frequency

Abstract: Device for generating a signal of parametrizable frequency comprising a phase locked loop including a generator of a reference signal, a phase-frequency comparator comprising a first input for receiving the reference signal, an oscillator controlled on the basis of the result output by the phase-frequency comparator, a fractional divider coupled between an output of the oscillator and a second input of the phase-frequency comparator, and a selector selectively linking an input of the oscillator either with an input of the generator, or with the output of the oscillator as a function of the multiplication ratio of the fractional divider.

Design of a MOS RLC-oscillator with specified total harmonic distortion

Abstract: Operation of a MOS RLC-oscillator is considered, and it is shown that it can be described by the van der Pol model. The transformation of time scale to the oscillator intrinsic time allows one to use the previously obtained results for harmonic content of the van der Pol model. One can calculate the total harmonic distortions and use it to design an oscillator with required level of them. The correction of frequency in case of strongly distorted oscillations is also given. The results are verified by design and simulation of an RLC-oscillator for realization in 130 nanometer technology for communications in wireless test systems.

A novel noncontact electromagnetic field-based sensor for the monitoring of resonant fatigue tests

Abstract: In this paper, a prototype of an electromagnetic field-based (EFB) vibration sensor that uses a novel sensing technique to monitor the resonant fatigue testing of a conductive and/or ferromagnetic target specimen is presented. The distance from the target to a coil within the sensor affects the impedance of the coil. The electronic circuitry for the sensor consists of a relaxation oscillator, an embedded microprocessor module and a high-speed digital-to-analog converter. The impedance of the coil determines the frequency of oscillation of the relaxation oscillator's output, so that vibration of the target causes changes in the oscillation frequency. A?timer in the embedded microprocessor module is used to count the oscillations, producing a digital signal that indicates the coil-to-target distance. The digital signal is instantaneously converted to an analog signal to produce the sensor's output. The key technologies proposed include: (1)?a novel timer counting method using the input capture functionality and timer of the embedded microprocessor module and (2)?significant simplification of the analog electronic circuitry. The performance of the proposed sensor has been verified using AISI 1095 carbon steel and Al6061?T6 aluminum alloy specimens during resonant fatigue tests. The sensor shows a good linearity between displacement amplitudes and output voltages.

The Study on Voltage Controlled Oscillator in Electronic Applications

Abstract: A low power and low phase-noise CMOS VCO Based on biasing of oversized MOS transistors is demonstrated. The LC-VCO used here dissipates 0.1114 mW power under 1.8 V supply voltage. The VCO frequency can be tuned from 11.6 to 12.5 GHz with a measured phase noise of 106 dBc/Hz at 400 kHz offset from 12.5 GHz oscillation frequency. Common figures of merit are 185.

Flicker indicating tube for blowout of simple electric appliance alternating current fuse

Abstract: A flicker indicating tube for blowout of a simple electric appliance alternating current fuse is characterized in that a flicker indicator device is connected in parallel at two ends of an alternating current fuse in various electric appliances without using a switching power supply, namely, a strip-shaped circuit board with the same length is arranged in a transparent plastic tube, a rectifier diode is arranged on the circuit board for rectification, a resistor is connected in series for reducing voltage and limiting current, and a relaxation oscillator formed by connecting a capacitor with a two-way trigger diode in series and connecting with a blue light-emitting diode in series is connected in series, the width of the circuit board is identical with the inner diameter of the transparent plastic tube, the height of all elements on the circuit board does not exceed the inner radius of the transparent plastic tube, and two wires are led out to be connected with two ends of the alternating current fuse in parallel.

Electronic hypnotic device using one battery only

Abstract: The utility model belongs to the field of electronic techniques and relates to an electronic hypnotic device using one battery only. The electronic hypnotic device consists of a direct-current power supply DC, a high-voltage generator, a high-voltage rectifier and filter circuit and a neon bulb relaxation oscillator, and is characterized in that the high-voltage generator is an inductive feedback oscillator, and an oscillating capacitor in a circuit of the neon bulb relaxation oscillator uses a piezoelectric ceramic wafer B1. Rhythmic moderate sounds can stabilize the emotion of people, nerves are enabled to be calmed down, a brain is kept in a relaxed state, and therefore the people are enabled to be sleepy hazily. The electronic hypnotic device provided by the utility model is made just by using the principle. Within set time, the electronic hypnotic device can repetitively simulate rhythmic ticktack sounds produced by rainwater which drops down to a step. When an insomniac carefully listens to the drip, the insomniac can fall asleep very easily.

Scaling laws in the transient dynamics of firefly-like oscillators

Abstract: Fireflies constitute a paradigm of pulse-coupled oscillators. In order to tackle the problems related to synchronisation transients of pulse-coupled oscillators, a Light-Controlled Oscillator (LCO) model is presented. A single LCO constitutes a one-dimensional relaxation oscillator described by two distinct time-scales meant to mimic fireflies in the sense that: it is capable of emitting light in a pulse-like fashion and detect the emitted by others in order to adjust its oscillation. We present dynamical results for two interacting LCOs in the torus for all possible coupling configurations. Transient times to the synchronous limit cycle are obtained experimentally and numerically as a function of initial conditions and coupling strengths. Scaling laws are found based on dimensional analysis and critical exponents calculated, thus, global dynamic is restricted. Furthermore, an analytical orthogonal transformation that allows to calculate Floquet multipliers directly from the time series is presented. As a consequence, local dynamics is also fully characterized. This transformation can be easily extended to a system with an arbitrary number of interacting LCOs.