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Showing papers on "Relaxation oscillator published in 2010"


Journal ArticleDOI
TL;DR: An on-chip CMOS relaxation oscillator with voltage averaging feedback using a reference proportional to supply voltage is presented and achieves 7x reduction in accumulated jitter (at 1500th cycle) as compared to a oscillator without VAF.
Abstract: An on-chip CMOS relaxation oscillator with voltage averaging feedback using a reference proportional to supply voltage is presented. A voltage-averaging feedback (VAF) concept is proposed to overcome conventional relaxation oscillator problems such as sensitivity to comparator delay, aging, and flicker noise of current sources. A test-chip with typical frequency of 14.0 MHz was fabricated in a 0.18 μm standard CMOS process and measured frequency variations of ±0.16 % for supply changes from 1.7 to 1.9 V and ±0.19% for temperature changes from -40 to 125°C. The prototype draws 25 μA from a 1.8 V supply, occupies 0.04 mm2, and achieves 7x reduction in accumulated jitter (at 1500th cycle) as compared to a oscillator without VAF.

179 citations


Journal ArticleDOI
Urs Denier1
TL;DR: The application field for this oscillator is the clock generation of low-power wake-up functions for battery-operated systems and a detailed analysis of the oscillator, including the temperature performance, is derived and verified with experimental results.
Abstract: This paper presents the design of a low-voltage ultralow-power relaxation oscillator without external components. The application field for this oscillator is the clock generation of low-power wake-up functions for battery-operated systems. A detailed analysis of the oscillator, including the temperature performance, is derived and verified with experimental results. The oscillator operates at a typical frequency of 3.3 kHz and consumes 11 nW from a 1-V supply at room temperature, and a temperature drift of less than 500 ppm/°C is achieved over the temperature range of -20°C to 80°C. An efficient design implementation has resulted in a cell area of 0.1 mm2 in a standard 0.35- μm digital CMOS technology.

136 citations


Journal ArticleDOI
09 Mar 2010-Chaos
TL;DR: In this article, the authors analyzed the global stability properties of birhythmicity in a self-sustained system with random excitations and showed that the two frequencies are strongly influenced by the nonlinear coefficients α and β.
Abstract: We analyze the global stability properties of birhythmicity in a self-sustained system with random excitations. The model is a multi-limit-cycle variation in the van der Pol oscillator introduced to analyze enzymatic substrate reactions in brain waves. We show that the two frequencies are strongly influenced by the nonlinear coefficients α and β. With a random excitation, such as a Gaussian white noise, the attractor’s global stability is measured by the mean escape time τ from one limit cycle. An effective activation energy barrier is obtained by the slope of the linear part of the variation in the escape time τ versus the inverse noise intensity 1/D. We find that the trapping barriers of the two frequencies can be very different, thus leaving the system on the same attractor for an overwhelming time. However, we also find that the system is nearly symmetric in a narrow range of the parameters.

36 citations


Patent
30 Dec 2010
TL;DR: In this paper, a power conversion system with a feedback control loop is described, and a timer is used to disable the oscillator after a period following the opening of the feedback control loops.
Abstract: A circuit protects a power conversion system with a feedback control loop from a fault condition. The circuit has an oscillator having an input for generating a signal with a frequency and a timer connected to the oscillator input and to the feedback control loop. The timer disables the oscillator after a period following the opening of the feedback control loop to protect the power conversion system.

33 citations


Journal ArticleDOI
01 Sep 2010
TL;DR: A new relaxation oscillator whose oscillation frequency is less sensitive to supply voltage fluctuation is proposed, and a new integrating feedback is proposed to increase the lock range and hold the locked frequency in the absence of the injection signal.
Abstract: This paper proposes a low-power remote frequency calibration method for passive UHF wireless transponders. The frequency of the local oscillator of passive UHF wireless transponders is adjusted to the desired values using an injection-locked phase-locked loop (IL-PLL). A new relaxation oscillator whose oscillation frequency is less sensitive to supply voltage fluctuation is proposed. The power consumption of the proposed IL-PLL is minimized by operating it the subthreshold. A detailed analysis of the nonharmonic injection locking of relaxation oscillators, including locking and pulling dynamics, is presented. A new integrating feedback is proposed to increase the lock range and hold the locked frequency in the absence of the injection signal. The proposed IL-PLL has been fabricated in TSMC 0.18- μm 1.8-V six-metal 1-poly CMOS technology. The performance of the IL-PLL is validated using both simulation and measurement results. The measured power consumption of the IL-PLL with a 10-mV (640-pW) 1-MHz injection signal is 960 nW. The lock range of the IL-PLL is 30 kHz without integrating feedback and 400 kHz with integrating feedback. The frequency of the locked oscillator drifts over time at a rate of 5 Hz/ms when the external injection signal is removed.

25 citations


Proceedings ArticleDOI
16 Jun 2010
TL;DR: In this paper, the authors describe the first achievement of over 20,000 quality factors among on-chip relaxation oscillators and propose a power averaging feedback with a Chopped Amplifier to achieve a high Q which is close to MEMS oscillators.
Abstract: This paper describes the first achievement of over 20,000 quality factors among on-chip relaxation oscillators. The proposed Power Averaging Feedback with a Chopped Amplifier enables such a high Q which is close to MEMS oscillators. 1/f noise free design and rail-to-rail oscillation result in low phase noise with small area and low power consumption. The proposed oscillator can be applied to low noise applications (e.g. digital audio players) implemented onto a System on a Chip.

19 citations


Patent
26 Mar 2010
TL;DR: In this paper, a failsafe oscillator monitor and alarm circuit is proposed, which is a very low current usage circuit that charges a storage capacitor with clock pulses from the external oscillator when functioning normally and discharges the storage capacitance with a constant current sink if the external Oscillator stops functioning.
Abstract: A failsafe oscillator monitor and alarm circuit receives clock pulses from an external oscillator that if a failure thereto occurs, the failsafe oscillator monitor and alarm circuit will notify a digital processor of the external oscillator failure. The failsafe oscillator monitor and alarm circuit is a very low current usage circuit that charges a storage capacitor with clock pulses from the external oscillator when functioning normally and discharges the storage capacitor with a constant current sink if the external oscillator stops functioning. When the voltage charge on the storage capacitor becomes less than a reference voltage an alarm signal is sent to the digital processor for exception or error handling of the failed external oscillator.

15 citations


Proceedings ArticleDOI
Bo Zhou1, Rui He1, Jian Qiao1, Jinghui Liu1, Woogeun Rhee1, Zhihua Wang1 
01 Nov 2010
TL;DR: In this article, the authors describe the architecture and circuit design of a low data rate FM-UWB transmitter with a Δ-Σ fractional-N PLL with a multi-phase relaxation oscillator to enable sub-carrier modulation with reduced quantization noise.
Abstract: This paper describes the architecture and circuit design of a low data rate FM-UWB transmitter. A Δ-Σ fractional-N PLL with a multi-phase relaxation oscillator is designed to enable sub-carrier modulation with reduced quantization noise. The triangular waveform output of the relaxation oscillator directly modulates an LC VCO to have the UWB-compliant spectrum. The center frequency of the LC VCO is quasi-continuously tuned by a Δ-Σ DAC based frequency-locked loop with the power consumption of 1.1mW. The 3.43–4.03GHz FM-UWB transmitter implemented in 0.18μm CMOS consumes the total power of 9.6mW.

15 citations


Proceedings ArticleDOI
04 Jul 2010
TL;DR: In this article, a low-power high-resolution CMOS interface for capacitive sensors with capacitance values from 1 pF up to 220 pF has been proposed, which can be used to eliminate the undesired effects of transfer-parameter drift.
Abstract: This paper presents a low-power high-resolution CMOS interface for capacitive sensors. The circuit is based on the use of a switched-capacitor charge amplifier, which converts the input capacitance to a voltage, which modulates the period of a relaxation oscillator. Auto-calibration is used to eliminate the undesired effects of transfer-parameter drift. The interface is suited for capacitive sensors with capacitance values from 1 pF up to 220 pF. Moreover, the measurement time can be set from about100 µs up to 50 ms. For the 10 pF range, parasitic capacitances up to 680 pF can be handled while the settling accuracy is more than 14 bits. For a measurement time of 1s, the resolution can be as high as 20 bits. In the 10 pF range, for parasitic capacitance up to 680 pF, the measured nonlinearity error is less than 5×10−5. All these features have been achieved with a chip consuming only 3 mm2 of silicon area and 5 mW of power.

15 citations


Journal ArticleDOI
TL;DR: A closely related system that exhibits relaxation oscillations and that approximates the cell cycle oscillator for an intermediate range of negative feedback strengths is constructed, and it is shown that thecell cycle oscillation disappears if the negative feedback is too weak or too strong.
Abstract: We study a finite-dimensional monotone system coupled to a slowly evolving scalar differential equation which provides a negative feedback to the monotone system. We use a theory of multivalued characteristics to show that this system admits a relaxation periodic orbit if a simple model system in $\mathbf{R}^2$ does. Our construction can be used to prove the existence of periodic orbits in slow-fast systems of arbitrary dimension. We apply our theory to a model of a cell cycle in Xenopus embryos. Abrupt changes in signals upon entry to mitosis suggests that the cell cycle is generated by a relaxation oscillation. Our results show that the cell cycle orbit is not a relaxation oscillator. However, we construct a closely related system that exhibits relaxation oscillations and that approximates the cell cycle oscillator for an intermediate range of negative feedback strengths. We show that the cell cycle oscillation disappears if the negative feedback is too weak or too strong.

14 citations


Proceedings ArticleDOI
01 Nov 2010
TL;DR: A comparison of the most widely used capacitance to frequency (CtoF) converters found in the bibliography with a newly concept of relaxation oscillator circuit redesigned for raw sensors conditioning applications is presented in this paper.
Abstract: This paper presents a comparison of the most widely used capacitance to frequency (CtoF) converters found in the bibliography with a newly concept of relaxation oscillator circuit redesigned for raw sensors conditioning applications.

Patent
Chataigner Emmanuel1
15 Jun 2010
TL;DR: In this article, an oscillating device comprising several oscillators (OSC1, OSC2), each oscillator comprising a capacitive inductive resonant circuit (L 1 & C 1, L 2 & C 2) and a flow-through conduction circuit (G1, G2) having a negative flow-passive conduction, the inductive elements of the oscillators being mutually coupled.
Abstract: Oscillating device comprising several oscillators (OSC1, OSC2), each oscillator comprising a capacitive inductive resonant circuit (L 1 & C1, L2 & C2) and a flow-through conduction circuit (G1, G2) having a negative flow-through conduction, the inductive elements of the oscillators being mutually coupled. Each oscillator also comprises a controllable switch (INT 1, INT2) arranged in order to short-circuit or not short-circuit the capacitive element of the oscillator (C1, C2) and in that the device also comprises controllable commutating means (STOP1, ST0P2) arranged to activate one oscillator at a time.

Journal ArticleDOI
TL;DR: In this paper, the effects of pulse stimulations on the dynamics of relaxation oscillator populations were experimentally studied in a globally coupled electrochemical system, where the pulse-induced transient clusters were interpreted with a phase model that includes first and second harmonics in the interaction function and exhibits saddle type cluster states with strongly stable intra-cluster and weakly unstable inter-clusters modes.

Patent
24 Feb 2010
TL;DR: In this paper, a passive ultra-high frequency radio frequency identification chip analog front circuit is presented, where a circuit is controlled by analog decoding to detect input PIE signals, a first integrator, a second integrator and a third integrator are controlled to integrate in set time respectively.
Abstract: The invention discloses a passive ultrahigh frequency radio frequency identification chip analog front circuit, mainly solving the problems that the existing circuit has larger power consumption and needs calibrating clock frequency when generating a backscatter link frequency. A circuit is controlled by analog decoding to detect input PIE signals, a first integrator, a second integrator and a third integrator are controlled to integrate in set time respectively, the integration results of the first integrator and the second integrator are compared by a comparer to finish decoding on the PIE signals; at the third falling edge behind a starting delimiter, an enable signal is generated according to the data preserved by a first register and the output of the first comparer, to control a relaxation oscillator in combination with the voltage generated by the third integrator, thus obtaining the backscatter link frequency required by a reader-writer. The invention has the advantages of lowpower consumption and no need for frequency calibration, and can be applied to passive ultrahigh frequency radio frequency identification chip design.

Patent
09 Jun 2010
TL;DR: In this paper, a multivibrator circuit and a voltage conversion circuit in which oscillation frequency can be stabilized even if the FET characteristics vary while achieving a lower voltage and lower current consumption are presented.
Abstract: PROBLEM TO BE SOLVED: To provide a multivibrator circuit and a voltage conversion circuit in which oscillation frequency can be stabilized even if the FET characteristics vary while achieving a lower voltage and lower current consumption.SOLUTION: The multivibrator circuit has a first FET 21 and a second FET 22, a first resistor R21 and a second resistor R22 as loads, a third resistor R23 connected between the gate of the second FET 22 and a power supply voltage source, a fourth resistor R24 connected between the gate of the first FET 21 and the power supply voltage source, a first capacitor C21 connected between the drain of the first FET 21 and the gate of the second FET 22, a second capacitor C22 connected between the drain of the second FET 22 and the gate of the first FET 21, a third diode connection FET 23 connected between the gate of the first FET 21 and the ground potential, and a fourth diode connection FET 24 connected between the gate of the second FET 22 and the ground potential.

Journal ArticleDOI
TL;DR: In this article, the authors numerically demonstrated that a resistive superconducting quantum interference device (RSQUID) with two nonhysteretic Josephson junctions works as a relaxation oscillator.
Abstract: The author numerically demonstrates that a resistive superconducting quantum interference device (RSQUID) with two nonhysteretic Josephson junctions works as a relaxation oscillator. Sequential switching of the Josephson junctions transfers positive and negative flux quanta in the RSQUID loop one by one. Differently from a conventional two-junction superconducting quantum interference device, the dissipative RSQUID loop does not maintain the quantized flux, and hence, finite flux can be accumulated in the RSQUID loop during sequential switching of the Josephson junctions. When the accumulated flux reaches a critical value, the corresponding loop current prevents subsequent junction switching. That is, the oscillation stops. After the loop current decays, sequential switching of the junctions resumes. In addition to the waveforms of relaxation oscillation, dependence of relaxation oscillation on device parameters is presented.

Patent
24 Feb 2010
TL;DR: In this paper, a passive ultra-high frequency radio frequency identification chip backscatter link frequency generation circuit and a method for solving the problems that the existing circuit has larger power consumption and needs frequency calibration are presented.
Abstract: The invention discloses a passive ultrahigh frequency radio frequency identification chip backscatter link frequency generation circuit and a method, mainly solving the problems that the existing circuit has larger power consumption and needs frequency calibration. In the invention, input PIE signals are detected, a first integrator and a second integrator are controlled to integrate in set time,and the integration results are compared by a comparer; at the second falling edge after an order begins, a third integrator is controlled to integrate; at the third falling edge after an order begins, the third integrator is controlled to stop integrating, and if the data preserved by a register is 0, the output of the comparer is written into the register; the output voltage of the third integrator and the data preserved by the register are used for controlling a relaxation oscillator to obtain backscatter link frequency required by a reader-writer. The invention has the advantages of low power consumption and no need for frequency calibration, and can be applied to passive ultrahigh frequency radio frequency identification chip backscatter link frequency generation circuit.

Patent
17 Nov 2010
TL;DR: In this article, a hypnotic electronic metronome is described, which is characterized by comprising an electric energy storage element, a relaxation oscillator and a piezoelectric ceramic plate (HTD).
Abstract: The utility model discloses a hypnotic electronic metronome which is characterized by comprising an electric energy storage element, a relaxation oscillator and a piezoelectric ceramic plate (HTD) which are sequentially connected, wherein the relaxation oscillator has the oscillating frequency of 0-8 Hz, the relaxation oscillator is formed by connecting a capacitor (2) with a resistor (R2) in parallel and then with a voltage-controlled electronic switch in series; the piezoelectric ceramic plate (HTD) is connected with the voltage-controlled electronic switch in parallel; and the electric energy storage element is connected with the relaxation oscillator in parallel. The beat frequency of the hypnotic electronic metronome decreases in the range of 0-8 Hz, which is consistent with the experiment result of the experimental psychology. The hypnotic electronic metronome has remarkable effect on inducing the physiological sleep of people.

Dissertation
01 Jan 2010
TL;DR: In this article, a wideband MOS current/voltage controlled quadrature oscillator constituted by two multivibrators is presented, and two different forms of coupling, traditional and hard, are investigated.
Abstract: Faculdade de Ciencias e Tecnologia Departamento de Engenharia Electrotecnica e de Computadores Mestre em Engenharia Electrotecnica e de Computadores by Hugo Filipe da Rocha Lopes This thesis proposes a study of three di erent RC oscillators, two relaxation and a ring oscillator All the circuits are implemented using UMC 130 nm CMOS technology with a supply voltage of 12 V We present a wideband MOS current/voltage controlled quadrature oscillator constituted by two multivibrators Two di erent forms of coupling named, soft (traditional) and hard (proposed) are di erentiated and investigated It is found that hard coupling reduces the quadrature error and results in a low phase-noise (about 2 dB improvement) with respect to soft coupling The behaviour of the singular and coupled multivibrators is investigated, when an external synchronizing harmonic is applied We introduce a new RC relaxation oscillator with pulse self biasing, to reduce power consumption, and with harmonic ltering and resistor feedback, to reduce phase-noise The designed circuit has a very low phase-noise, -1326 dBc/Hz @ 10 MHz o set, and the power consumption is only 1 mW, which leads to a gure of merit (FOM) of -1591 dBc/Hz The nal circuit is a two integrator fully implemented in CMOS technology, with low power consumption The respective layout is made and occupies a total area of 5856x10−3 mm, post-layout simulation is also done UNIVERSIDADE NOVA DE LISBOA

Dissertation
01 Jan 2010
TL;DR: In this article, a new approach to active inductor oscillator design using self-oscillating active inductors has been presented, where the instability necessary to start oscillations is provided by the use of a passive RC network rather than a power consuming external circuit.
Abstract: Voltage controlled oscillators (VCOs) are essential components of RF circuits used in transmitters and receivers as sources of carrier waves with variable frequencies This, together with a rapid development of microelectronic circuits, led to an extensive research on integrated implementations of the oscillator circuits One of the known approaches to oscillator design employs resonators with active inductors electronic circuits simulating the behavior of passive inductors using only transistors and capacitors Such resonators occupy only a fraction of the silicon area necessary for a passive inductor, and thus allow to use chip area more eectively The downsides of the active inductor approach include: power consumption and noise introduced by transistors This thesis presents a new approach to active inductor oscillator design using selfoscillating active inductor circuits The instability necessary to start oscillations is provided by the use of a passive RC network rather than a power consuming external circuit employed in the standard oscillator approach As a result, total power consumption of the oscillator is improved Although, some of the active inductors with RC circuits has been reported in the literature, there has been no attempt to utilise this technique in wideband voltage controlled oscillator design For this reason, the dissertation presents a thorough investigation of self-oscillating active inductor circuits, providing a new set of design rules and related trade-os This includes: a complete small signal model of the oscillator, sensitivity analysis, large signal behavior of the circuit and phase noise model The presented theory is conrmed by extensive simulations of wideband CMOS VCO circuit for various temperatures and process variations The obtained results prove that active inductor oscillator performance is obtained without the use of standard active compensation circuits Finally, the concept of self-oscillating active inductor has been employed to simple and fast OOK (On-Off Keying) transmitter showing energy eciency comparable to the state of the art implementations reported in the literature

Journal ArticleDOI
TL;DR: In this paper, a thermal flow sensor with smart electronic interface is presented, which is based on four germanium thermistors embedded in a thin membrane, and the thermistors form a Wheatstone bridge supplied with a constant current.

Patent
05 May 2010
TL;DR: In this paper, a static magnetic part arranged opposite to printed circuit boards, and inductors (L1-L32) are attached on the circuit board, and connected with an oscillator.
Abstract: The device has a stationary magnetic part arranged opposite to printed circuit boards, and inductors (L1-L32) ie coils, determining position of the magnetic part The coils are attached on the circuit board, and connected with an oscillator (1) Output signal of the oscillator has a frequency that is dependent on a relative position of a movable magnetic part (M) towards the coil, and connected with a microprocessor The oscillator has a feedback operational amplifier (VI) and a capacitor (C2), which forms a frequency-determining inductor capacitor element of the oscillator

Patent
21 Oct 2010
TL;DR: In this article, a clock oscillator is formed as a feedback Schmitt trigger and guiding a drain-source voltage of a power transistor to an input of comparators through voltage dividers (RD, Rm).
Abstract: The supply unit has a clock oscillator (13) formed as a feedback Schmitt trigger and guiding a drain-source-voltage of a power transistor to an input of comparators (26) i.e. Schmitt trigger (14.3), through voltage dividers (RD, Rm). An output of the comparator is guided to a feedback point (A) of the oscillator through a coupling network (28) i.e. parallel resistor-capacitor member. An output signal of a control amplifier (18) is added to a signal proportional to a switching current, and a summing signal corresponding to the voltage value is assigned to the feedback point of the oscillator.

Patent
28 Sep 2010
TL;DR: In this paper, the authors described a voltage controlled oscillator with a fine-tuning varactor network, a switch capacitor array having a first plurality of binary capacitor array elements and a second plurality of thermometer code capacitor array element.
Abstract: The described devices, systems and methods include a voltage controlled oscillator. The voltage controlled oscillator includes a fine-tuning varactor network, a switch capacitor array having a first plurality of binary capacitor array elements and a second plurality of thermometer code capacitor array elements, and a tank inductor network including a first inductor in parallel with a second inductor.

Proceedings ArticleDOI
01 Nov 2010
TL;DR: In this article, a thermal flow sensor with smart electronic interface is presented, which is based on four germanium thermistors embedded in a thin membrane and connected to form a Wheatstone bridge.
Abstract: A thermal flow sensor with smart electronic interface is presented. The sensor is based on four germanium thermistors embedded in a thin membrane and connected to form a Wheatstone bridge. Both the bridge unbalance voltage and the voltage at the bridge supply terminals under constant current excitation are functions of the flow offering high initial sensitivity and wide measurement range, respectively. The signal interface is based on a relaxation oscillator which provides a rectangular-wave output whose frequency is related to the bridge unbalance, whereas the duty cycle is a function of the voltage at the bridge supply terminals. Hence, both sensor signals are simultaneously and independently carried on the same output signal, featuring unambiguous characteristic over a wide flow range accompanied with a high relative sensitivity at low flow velocities. The amplitude of the output signal depends linearly on the operating temperature, which enables the correction of the temperature dependence of the sensor readouts.

Proceedings ArticleDOI
14 Mar 2010
TL;DR: In this paper, an interface circuit for capacitive sensors that are shunted by a parasitic leakage conductance and which are grounded at one of their electrode terminals is designed based on the use of a relaxation oscillator.
Abstract: The paper presents an interface circuit for capacitive sensors that are shunted by a parasitic leakage conductance and which are grounded at one of their electrode terminals The electronic circuit is designed based-on the use of a relaxation oscillator In the designed interface, the effect of shunting conductance is reduced by using the charge/discharge-balanced method The parasitic effects of the guarding electrode and stray capacitances are eliminated by using so-called feedforward-based active-shielding technique The use of auto-calibration and chopping eliminates all multiplicative and additive errors of the interface A prototype has been built for sensor capacitances in the range of the 0 pF ~ 330 pF with shunting conductance up to Gs = 10 μS and a measurement time of 75 ms The experimental results show a maximum error of 23 pF (07%FS) and a standard deviation due to noise of 127 fF (0004%FS)

Journal ArticleDOI
TL;DR: A detailed nonlinear analysis and design of a distributed voltage controlled oscillator (DVCO) is presented in this work and a DVCO operating in the frequency tuning range between 1 and 2 GHz has been implemented in order to support the simulation results.
Abstract: A detailed nonlinear analysis and design of a distributed voltage controlled oscillator (DVCO) is presented in this work. The analysis and design of the DVCO is performed using harmonic balance-based simulation techniques and envelope transient simulation. These techniques are used to make a complete nonlinear study of the behavior of the DVCO. Using the proposed nonlinear tools, a DVCO operating in the frequency tuning range between 1 and 2 GHz has been implemented in order to support the simulation results. The average output power and consumption along the frequency band for the designed DVCO are 5.2 dBm and 60.4 mW, respectively.

Proceedings ArticleDOI
28 Mar 2010
TL;DR: In this article, the impact of RF interference on relaxation oscillators is discussed and a test mode implementation is proposed to implement test mode in microcontrollers and other complex SOCs, allowing yet characterization and fault debug.
Abstract: Nowadays some microcontroller clock circuits have been implemented using relaxation oscillators instead of quartz type approach to attend cost effective designs. The oscillator is compensated over temperature and power supply and trimming during device test phase adjusts the oscillation frequency on target to overcome process variations. In that way, the relaxation oscillator becomes competitive with regard to ceramic resonator options. However, robust applications as industrial, automotive and aero spatial, requires aggressive EMC tests reproducing the behavior in these environments. High levels of RF interference introduce frequency deviation, jitter or clock corruption causing severe faults on the application. This work discusses the impact of RF interference in relaxation oscillators proposing a strategy to implement test mode in microcontrollers and other complex SOCs, allowing yet characterization and fault debug. Theoretical analysis and experimental results with a silicon implementation are presented and discussed.

Proceedings ArticleDOI
25 Oct 2010
TL;DR: The quasi-linear van der Pol oscillator subject to parametric excitation applied on its natural frequency is studied to determine whether parametricexcitation could be helpful for synchronization of oscillators.
Abstract: The quasi-linear van der Pol oscillator subject to parametric excitation applied on its natural frequency is studied. The effect of this parametric excitation is analyzed, regular perturbation theory is used to determine the effect on the resulting frequency of oscillation; phase plane analysis and averaging method are both used to determine the effect on the amplitude of the solution. Having an external signal, the results help foreseeing the forcing strength required to suppress the natural frequency of the parametrically excited oscillator; or the one required by the parametrically excited oscillator to suppress the natural frequency of a second oscillator. This is a first approach to determine whether parametric excitation could be helpful for synchronization of oscillators.

Proceedings ArticleDOI
28 Jun 2010
TL;DR: An averaging method is used, which is a technique for nonlinear system analysis, to derive an approximated model of a spring-mass system driven by the VDP oscillator, and prove the entrainment property of the V DP oscillator that realizes efficient large force generation based on the model.
Abstract: This paper presents a mathematical proof of the entrainment property of Van der Pol (VDP) oscillator driving a spring-mass system for large force generation. The entrainment property enables the mechanical system to generate a large force despite smaller amount of driving torques. Although it has been already confirmed by simulations using a manipulator model that a method with the VDP oscillator is effective in efficient large force generation, any mathematical proof that supports the simulation results has not been provided yet. In this paper, using an averaging method, which is a technique for nonlinear system analysis, we derive an approximated model of a spring-mass system driven by the VDP oscillator, and then prove the entrainment property of the VDP oscillator that realizes efficient large force generation based on the model.