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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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Patent
13 Aug 1968

5 citations

Patent
C Lai1
26 Oct 1972
TL;DR: In this paper, an analog-to-pulse-width converter (A2PWC) is proposed, where an analog voltage representing the oil pressure of an internal combustion engine is applied at the input of the circuit to charge the capacitor of the multivibrator to the voltage level of the analog voltage.
Abstract: An analog to pulse width converter circuit includes a monostable multivibrator. The circuit is maintained in a first stable state by a constant current source. An analog voltage representing, for example, the oil pressure of an internal combustion engine is applied at the input of the circuit to charge the capacitor of the multivibrator to the voltage level of the analog voltage. A sample oscillator applying pulses periodically to the circuit triggers the latter to operation in a second, active state, whereby an output is provided from the circuit. Upon operation to the active state, the constant current source charges the capacitor in the opposite direction; the reverse charging time being determined by the original charge on the capacitor at the time of application of the trigger pulse. The duration of the circuit output is thus equal to the reverse charging time and directly related to the voltage level of the analog voltage. Additional circuitry including a clock oscillator, AND gate and pulse converter may be employed in conjunction with the analog to pulse width converter circuit to provide an analog to digital converter.

5 citations

Patent
18 Mar 2015
TL;DR: In this article, an ultra-low power oscillator is designed for wake-up timers that can be used in compact wireless sensors, and a constant charge subtraction scheme removes continuous comparator delay from the oscillation period, which is the source of temperature dependence in conventional RC relaxation oscillators.
Abstract: An ultra-low power oscillator is designed for wake-up timers that can be used in compact wireless sensors, for example. A constant charge subtraction scheme removes continuous comparator delay from the oscillation period, which is the source of temperature dependence in conventional RC relaxation oscillators. This relaxes comparator design constraints, enabling low power operation. In 0.18 μm CMOS, the oscillator consumes 5.8 nW at room temperature with temperature stability of 45 ppm/° C. (−10° C. to 90° C.) and 1%/V line sensitivity.

5 citations

Patent
09 Sep 1969
TL;DR: In this article, alternating current analogue signals are combined to a third signal representing product or difference by applying one such signal (or a combination thereof) to a switch input generating a pulse control signal from the other thereof to control the switch operation between conducting and non conducting and filtering the switch output to produce the required signal.
Abstract: 1,202,073. Product; difference computing. AMERICAN OPTICAL CORP. 22 Nov., 1967 [1 Dec., 1966], No. 53273/67. Heading G4G. Alternating current analogue signals are combined to a third signal representing product or difference by applying one such signal (or a combination thereof) to a switch input generating a pulse control signal from the other thereof to control the switch operation between conducting and non conducting and filtering the switch output to produce the required signal. In Fig. 1, signals V A and -V B of identical frequency in antiphase (e.g. from the photo-cell outputs of a dual beam spectrophotometer) are applied to inputs 10, 12 from which they are algebraically added at junction 14 to produce error signal V s applied to a switching circuit (Fig. 3, not shown) comprising a transformer fed biased amplifier having a pulsed transistor alternately connecting and disconnecting the input to earth. Input V A is also amplified to constant amplitude V c which is applied to control the frequency of the output V o of a relaxation oscillator 20 according to its instantaneous voltage values, to drive a oneshot multivibrator 22, whose output is thus a sinusoidally frequency multiplied pulse train, to pulse the switch 16 (Fig. 2, not shown), whose output is integrated in low pass filter 24, to a direct voltage V F which is shown by mathematics to be combined of a constant voltage V R and a voltage proportional to the product V c , V s . Amplification by differential D.C. amplifier 26 receiving a voltage V R produces an output proportional to V c , V s and thus to (V A -V B ) since V C is constant. This signal may be applied to a null balance servosystem controlling V A and -V B for null error. Alternatively the output represents the product of (V A -V B ) V C where V C is proportional to V A . Where V A and V B are applied directly to the relaxation oscillator and the switch respectively, the output is proportional to the product V A , V B .

5 citations

Journal ArticleDOI
TL;DR: In this paper, a novel oscillator core is introduced, which ensures good control linearity and insensitivity to CMOS variations of the output frequency as a prerequisite for frequency and temperature calibration.
Abstract: In this work, the design methodology of the relaxation oscillator with the post-processing trimming option for frequency and temperature coefficient is presented. A novel oscillator core is introduced, which ensures good control linearity and insensitivity to CMOS variations of the output frequency as a prerequisite for frequency and temperature calibration. The proposed oscillator operates at 2 MHz and consumes typically about $I_{DD}=97.8\,\,\mu \text{A}$ at the nominal temperature of 42.5°C and nominal supply voltage of $V_{DD}=1.8$ V. The oscillator is verified experimentally with 10 samples manufactured in 180 nm CMOS process, each covering an area of 0.075 mm2. The frequency and temperature calibration was performed based on the two-point temperature measurements, resulting in a significant improvement in frequency stability. The temperature calibrated oscillator has a temperature variation ±0.30% in the temperature range from −40°C to 125°C, and the variation with the power supply ±0.07% in the supply range from 1.62 V to 1.98 V.

5 citations


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