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Relaxation oscillator

About: Relaxation oscillator is a research topic. Over the lifetime, 1952 publications have been published within this topic receiving 22326 citations.


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Proceedings ArticleDOI
01 Jun 2018
TL;DR: A pW-power versatile relaxation oscillator operating from sub-threshold to nominal voltage and low sensitivity of frequency/absorbed current to the supply allow the suppression of the voltage regulator, and direct powering from harvesters or 1.2-1.5V batteries.
Abstract: A pW-power versatile relaxation oscillator operating from sub-threshold (0.3V) to nominal voltage (1.8V) is presented, having Hz-range frequency under sub-pF capacitor. The wide voltage and low sensitivity of frequency/absorbed current to the supply allow the suppression of the voltage regulator, and direct powering from harvesters (e.g., solar cell, thermal from machines) or 1.2-1.5V batteries. A 180nm testchip exhibits a frequency of 4 Hz, 10%/V supply sensitivity at 0.3-1.8V, 8-18pA current, 4%/°C thermal drift from −20°C to 40°C.

13 citations

Patent
21 Sep 1959
TL;DR: In this paper, a system for measuring the interval between the generation of an elastic impulse at a transmitter positioned in a well bore and its reception at a receiver supported in a predetermined spaced relation from said transmitter is described.
Abstract: 774,098. Geophysical prospecting. SOCONY MOBIL OIL CO., Inc. Aug. 16, 1954, No. 23783/54. Class 118 (2). A system for measuring the interval between the generation of an elastic impulse at a transmitter positioned in a well bore and its reception at a receiver supported in a predetermined spaced relation from said transmitter comprises means for generating a voltage that varies monotonically from a predetermined initial value following the generation of said elastic impulse, a capacitive element, a switching circuit including normally non-conductive electron discharge means interconnecting said capacitive element and said sources of monotonically varying voltage, means effective in response to the arrival of said elastic impulse at said receiver for momentarily closing said switching circuit for flow of current therethrough to charge said capacitive element to a voltage equal to the magnitude of said monotonically varying voltage at the instant of arrival of said elastic impulse at said receiver, and means for measuring the voltage across the capacitive element. A cable 413, which may have a tension member in addition to transmitter and receiver conductors 414 and 415, carries a transmitter 410, comprising a relaxation oscillator pulsing a piezo-electric crystal 428, and a receiver 411. Transmitter 410 and receiver 411 are maintained at a predetermined spacing and may be moved up and down within the bore-hole 412. Transmitter 410 produces a pulse as indicated at 440 (Fig. 2) which may repeat, for example, 100 times per second. A gating unit 433 produces a negative voltage 441, in response to triggering by the transmitter 410, and controls a voltage generator 434 which provides a saw-tooth voltage as at 442. The length of the gate 441 is made greater than the time of travel of an elastic pulse in the lowest velocity formations to be investigated, but shorter than the period of the pulse repetition rate. The gain of amplifier 430 is also controlled by gating unit 433 to vary in the manner indicated at 443. A signal from the receiver 411 (as at 444) is thus amplified and fed to blocking oscillator 431 which provides a pulse 445 to operate an electronic switch 432. This momentarily connects a condenser to the voltage generator 434 so that it takes up the instantaneous voltage as indicated at 446 in Fig. 2. This occurs at the pulse repetition frequency and the voltage on the condenser will vary in accordance with the time interval #t (Fig. 2) dependent upon the velocity of the elastic impulses in the part of the well bore wherein the transmitter and receiver are situated. The voltage on the condenser is recorded on a recorder 435 driven by a pulley 437 whereby the movement of the recording chart is made proportional to the movement of the cable 413. Conventional circuitry for units 430 to 434 inclusive is given in Fig. 3 (not shown). A modification (Fig. 4, not shown) utilizes two receivers at a predetermined spacing and the signal from the receiver nearer to the transmitter triggers the gating unit 433. An auxiliary gating unit is provided to prevent triggering of unit 433 by the transmitter pulse due to cross-feed in the cable 413. Alternatively the battery 421 may be located down-hole in the housing of the transmitter, and thereby eliminate one conductor in the cable 413 and cross-feed therefrom. Instead of a saw-tooth voltage from generator 434 a voltage decreasing according to a rectangular hyperbole which is the reciprocal of a sawtooth may be provided (Fig. 6, not shown). Thus, the voltage is representative of velocity instead of time and the recorder 435 plots the velocities in the various formations directly. Conventional circuitry for generation and utilization of such a hyperbolic waveform is disclosed in Fig. 5 (not shown).

13 citations

Proceedings ArticleDOI
19 May 2013
TL;DR: The design presented in this paper is based on a fully differential three-stage ring oscillator with replica feedback bias, a novel process detection circuit, and a novel differential comparator to save power and area.
Abstract: We present the design and performance of a power and area efficient, process and voltage compensated, 2-MHz clock oscillator for state-of-the art wireless biomedical implantable systems-on-chip. The design presented in this paper is based on a fully differential three-stage ring oscillator with replica feedback bias, a novel process detection circuit, and a novel differential comparator to save power and area. The design of the comparator ensures the rail-to-rail swing and further improves power-supply-rejection-ratio (PSRR). The process corner sensing scheme is based on the leakage current of the device which generates control voltage for the replica feedback bias circuit. A total of 66 chip samples were collected from various locations on multiple full wafers and average variation of ±2.81% with process corner was measured at room temperature. The variation in clock frequency with supply was 0.11% for the voltage range of 1.9V-3V. The design of oscillator is intended for the RF powering scheme and it occupies 0.018 μm2 in 0.18-μm CMOS. The clock oscillator consumes 12μW from a 1.8 V regulated supply.

13 citations

Patent
James E Thompson1
30 Nov 1970
TL;DR: In this paper, an integrated circuit which functions as a sinusoidal and square wave generator with a direct coupled automatic gain control to vary the current through the oscillator, so as to keep the gain of the oscillators at a figure less than that at which the nonlinearity of the circuit becomes significant.
Abstract: There is disclosed an integrated circuit which functions as a sinusoidal and square wave generator with a direct coupled automatic gain control to vary the current through the oscillator, so as to keep the gain of the oscillator at a figure less than that at which the nonlinearity of the circuit becomes significant. The automatic gain control portion of the circuit includes half-wave rectifying and peak following circuits which follow the peak to peak voltage in the oscillator section and control the current through the oscillator as a function of this voltage. The square wave generating circuit includes a half-wave rectifying circuit and a high gain amplifying section to provide a partially clipped square wave operating below a reference potential, making the square wave signal compatible with emitter coupled logic systems.

13 citations

Patent
15 Dec 1999
TL;DR: A relaxation oscillator for a transponder capable of measuring one or more parameters (e.g., temperature, pressure) in an object and transmitting a data stream to an external reader/interrogator is described in this paper.
Abstract: A relaxation oscillator for a transponder capable of measuring one or more parameters (e.g., temperature, pressure) in an object and transmitting a data stream to an external reader/interrogator. The transponder typically operates in a passive mode, deriving its power from an RF interrogation signal received by an antenna system, but c=also operate in a battery-powered active mode. The transponder includes memory for storing measurements, calibration data programmable trim settings, transponder ID and the like. Measurement readings comprise counting oscillations of a measurement signal during a fixed time window. The measurement signal is generated by a relaxation oscillator driven by the alternating charging and discharging of measurement capacitors. wherein the capacitor charging rate is a function of current, and of capacitance. By using a mirror measurement current lo discharge the measurement capacitors, the discharge rate is made approximately equal to the charge rate. The measurement current can be scaled according to programmed trim settings to independently optimize readings for the different measured parameters.

13 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202322
202242
202128
202044
201962
201855