Topic
Voltage-controlled oscillator
About: Voltage-controlled oscillator is a research topic. Over the lifetime, 23896 publications have been published within this topic receiving 231875 citations. The topic is also known as: VCO.
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TL;DR: This work analyzes the negative-gm LC model and presents a simple equation that quantifies output noise resulting from phase fluctuations, and derives an expression for output Noise resulting from amplitude fluctuations.
Abstract: Recent work by Bank, and Mazzanti and Andreani has offered a general result concerning phase noise in nearly-sinusoidal inductance-capacitance (LC) oscillators; namely that the noise factor of such oscillators (under certain achievable conditions) is largely independent of the specific operation of individual transistors in the active circuitry. Both use the impulse sensitivity function (ISF). In this work, we show how the same result can be obtained by generalizing the phasor-based analysis. Indeed, as applied to nearly-sinusoidal LC oscillators, we show how the two approaches are equivalent. We analyze the negative-gm LC model and present a simple equation that quantifies output noise resulting from phase fluctuations. We also derive an expression for output noise resulting from amplitude fluctuations. Further, we extend the analysis to consider the voltage-biased LC oscillator and fully differential CMOS LC oscillator, for which the Bank's general result does not apply. Thus we quantify the concept of loaded Q.
132 citations
TL;DR: In this paper, a 1-V integrated CMOS current-mode boost converter implemented in a standard 3.3/5-V 0.6-/spl mu/m CMOS technology (V/sub TH//spl ap/0.85 V), providing power-conversion efficiency of higher than 85% at 100-mA output current, is presented.
Abstract: A 1-V integrated CMOS current-mode boost converter implemented in a standard 3.3/5-V 0.6-/spl mu/m CMOS technology (V/sub TH//spl ap/0.85 V), providing power-conversion efficiency of higher than 85% at 100-mA output current, is presented in this paper. The high-performance boost converter is successfully developed due to three proposed low-voltage circuit structures, including an inductor-current sensing circuit for current-mode operation with accuracy of higher than 94%, a precision V-I converter for compensation-ramp generation in current-mode control, and a VCO providing supply-independent clock and ramp signals. Moreover, a proposed startup circuit enables proper converter startup within a sub-1-V supply condition.
132 citations
Patent•
29 Aug 1969
TL;DR: An oscillator circuit adapted particularly for use with transducers for producing energy in the ultrasonic frequency range in which a combination of feedback signals representative of the voltage across the transducers and the current through the transducer are used to more precisely lock the oscillator to the resonant frequency of the load.
Abstract: An oscillator circuit adapted particularly for use with transducers for producing energy in the ultrasonic frequency range in which a combination of feedback signals representative of the voltage across the transducer and the current through the transducer are used to more precisely lock the oscillator to the resonant frequency of the load to thereby provide improved power transfer from the oscillator to the transducer. A current control circuit is also provided to control the amount of shock delivered by the transducer.
128 citations
Patent•
13 Nov 2003
TL;DR: In this article, a transmission line configured as a looped-stub resonator is disclosed, which can be used as a frequency selective element for an oscillator, such as a VCO of a phase locked loop.
Abstract: A transmission line configured as a looped-stub resonator is disclosed, which can be used as a frequency selective element for an oscillator, such as a VCO of a phase locked loop. The transmission line is a fraction of an electrical wavelength, and can be embedded to provide an inner resonant layer of an overall layered structure. The transmission line is formed into a loop or multiple loops and may be terminated with a capacitor, short circuit, or open circuit. In the embedded case, dielectric insulating material can be used to surround the transmission line on top and bottom surfaces as layers. In addition, electrically conducting material layers can be used to surround the dielectric insulating material.
128 citations
Proceedings Article•
01 Jan 2006
TL;DR: A compact, closed-form phase noise equation is obtained, accounting for the noise contributions from both tank losses and transistors currents, which allows a robust comparison between LC oscillators built with either one or two switch pairs.
Abstract: This paper presents a rigorous phase noise analysis in the 1/f 2 region for the differential CMOS LC-tank oscillator with both nMOS and pMOS switch pairs. A compact, closed-form phase noise equation is obtained, accounting for the noise contributions from both tank losses and transistors currents, which allows a robust comparison between LC oscillators built with either one or two switch pairs. The fabricated oscillator prototype is tunable between 2.15 and 2.35 GHz, and shows a phase noise of -144 dBc/Hz at 3 MHz offset from the 2.3 GHz carrier for a 4 mA bias current. The phase noise figure-of-merit is practically constant across the tuning range, with a minimum of 191.5 dBc/Hz. A reference single-switch-pair oscillator has been implemented and tested as well, and the difference between the phase noise levels displayed by the two oscillators is very nearly the one expected from theory.
128 citations