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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
02 Oct 1991
TL;DR: In this paper, a source voltage detector compares the source voltage being applied to the crystal oscillator circuit with a predetermined reference voltage and produces a control signal matching whether the source voltages are higher or lower than the reference voltage.
Abstract: circuit whose oscillation frequency is dependent on source voltage applied thereto. When a capacitor is added to the frequency compensation terminal of the crystal oscillator circuit, the circuit changes the oscillation frequency thereof on the basis of the capacitance of the capacitor. A source voltage detector compares the source voltage being applied to the crystal oscillator circuit with a predetermined reference voltage and produces a control signal matching whether the source voltage is higher or lower than the reference voltage. On receiving the control signal, a control switch turns on or off the contact thereof to add or not to add the capacitor to the frequency compensation terminal. Assuming that the characteristic of the crystal oscillator circuit is such that the oscillation frequency decreases with the decrease in the source voltage, when the source voltage is low, the capacitor for frequency compensation is not added so as to increase the oscillation frequency of the crystal oscillator. Conversely, when the characteristic is such that the oscillation frequency increases with the decrease in the source voltage, the capacitor is added so as to decrease the oscillation frequency.
Journal ArticleDOI
TL;DR: A temperature-compensated high-frequency CMOS integrated relaxation oscillator with low frequency variations is presented, employed with a resistive source-degenerated transconductor and a current comparator to achieve high oscillation frequency and low power dissipation.
Abstract: A temperature-compensated high-frequency CMOS integrated relaxation oscillator with low frequency variations is presented A current-controlled oscillator topology is employed with a resistive source-degenerated transconductor and a current comparator to achieve high oscillation frequency and low power dissipation The proposed oscillator was designed with process parameters from a standard 035-$$\upmu $$μm CMOS technology and a 25-V single power supply voltage At a nominal oscillation frequency of 21 MHz, the total power dissipation of the circuit was 201 $$\upmu $$μW Post-layout simulation results showed that the frequency variations were less than $${3416\,\hbox {ppm}/{^{\circ }\hbox {C}}}$$3416ppm/?C over a temperature range of $$-40$$-40 to $$+120\,^{\circ }\hbox {C}$$+120?C
Patent
08 May 2002
TL;DR: In this article, a method for modulating an output voltage of a transmitter circuit comprising a voltage controlled oscillator, a digital/analog converter and an antenna circuit was proposed.
Abstract: The invention relates to a method for modulating an output voltage of a transmitter circuit comprising a voltage controlled oscillator, a digital/analog converter and an antenna circuit, the method comprising the method comprising sending an output signal of sufficient power from the voltage controlled oscillator directly to the antenna circuit and directly modulating a frequency of the output signal of the voltage controlled oscillator. The invention furthermore relates to a transmitter circuit comprising a voltage controlled oscillator having a tank circuit, a digital/analog converter and an antenna circuit, wherein the voltage controlled oscillator is adapted to send an output signal of sufficient power directly to the antenna circuit and wherein the digital/analog converter is arranged to modulate an output frequency of the voltage controlled oscillator. A capacitive load circuit may be connected to the tank circuit or a crystal oscillator circuit of the voltage controlled oscillator for modulating the frequency of the voltage controlled oscillator.
Patent
12 Jul 2006
TL;DR: In this paper, a voltage controlled oscillator is proposed to adjust the amplitude of the oscillation signals outputted and produces less phase noise than that of a prior art oscillator employing an adjustable current source.
Abstract: A voltage controlled oscillator 10 comprises a voltage controlled resonance circuit 11, a differential amplifying circuit 12 and an active load P1,P2 and outputs two oscillation signals OUT1, OUT2 having a phase difference of 180{ Automatic amplitude controller 20 rectifies the oscillation signals in peak detector 21, and the resulting direct voltage is filtered and compared with a threshold 23 in comparator 24 that controls active loads P1 ,P2 and thereby the gain of differential amplifying circuit 12 The invention adjusts the amplitude of the oscillation signals outputted and produces less phase noise than that of a prior art oscillator employing an adjustable current source (fig 1, Is) Resonance circuit 11 may comprise an inductor L1 and variable capacitors C1,C2 whose capacitance is varied by control voltage Vctl Differential amplifier circuit 12 may comprise N channel MOSFET transistors N1,N2 and the active load may comprise P channel MOSFET transistors P1,P2 whose gates are controlled by comparator 24 The oscillator may be used as the local oscillator in digital broadcast reception apparatus
Journal ArticleDOI
TL;DR: In this article, a DC-DC Converter with Relaxation Oscillator with Random Number Generator is proposed to minimize the electromagnetic interference (EMI) noise in RF receiver system.
Abstract: This paper proposes Relaxation Oscillator with Random Number Generator to minimize electromagnetic interference (EMI) noise. DC-DC Converter with Relaxation Oscillator is presented how much spurious noise effects to RF Receiver system. The main frequency of the proposed Relaxation oscillator is 7.9 MHz to operate it and add temperature compensation block to be applied to the frequency compensation in response to temperature changes. The DC-DC Converter Spurious noise is reduced up to 20 dB through changing frequency randomly. It is fabricated in 0.18 μm CMOS technology. The active area occupies an area of 220 μm×280 μm. The supply voltage is 1.8 V and current consumption is 500 μA.Key words: Relaxation Oscillator, EMI, Random Number Generator, Temperature Compensation tœžŸs— ž(College of Information & Communication Engineering, SungKyunKwan University) *SK i¢(SK Telecom)Manuscript received July 6, 2015 ; Revised September 4, 2015 ; Accepted September 11, 2015. (ID No. 20150706-07S)Corresponding Author: Kang-Yoon Lee (e-mail: klee@skku.edu)

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