Discrete clock generator and timing/frequency reference
First Claim
1. An integrated circuit comprising:
- a reference oscillator comprising an inductor and a capacitor, the reference oscillator adapted to provide a first reference signal having a first frequency;
a plurality of controlled reactance modules coupled to the reference oscillator, each reactance module of the plurality of reactance modules adapted to provide a selected reactance in response to a control voltage to maintain the first frequency substantially constant in a first operating mode; and
an output circuit adapted to provide an output interface for signal communication.
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Abstract
In various embodiments, the invention provides a discrete clock generator and/or a timing and frequency reference using an LC-oscillator topology, having a frequency controller to control and provide a stable resonant frequency, which may then be provided to other, second circuitry such as a processor or controller. Frequency stability is provided over variations in a selected parameter such as temperature and fabrication process variations. The various apparatus embodiments include a sensor adapted to provide a signal in response to at least one parameter of a plurality of parameters; and a frequency controller adapted to modify the resonant frequency in response to the second signal. In exemplary embodiments, the sensor is implemented as a current source responsive to temperature fluctuations, and the frequency controller is implemented as a plurality of controlled reactance modules which are selectively couplable to the resonator or to one or more control voltages. The controlled reactance modules may include fixed or variable capacitances or inductances, and may be binary weighted. Arrays of resistive modules are also provided, to generate one or more control voltages.
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Citations
53 Claims
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1. An integrated circuit comprising:
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a reference oscillator comprising an inductor and a capacitor, the reference oscillator adapted to provide a first reference signal having a first frequency; a plurality of controlled reactance modules coupled to the reference oscillator, each reactance module of the plurality of reactance modules adapted to provide a selected reactance in response to a control voltage to maintain the first frequency substantially constant in a first operating mode; and an output circuit adapted to provide an output interface for signal communication. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. An integrated circuit comprising:
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a reference harmonic oscillator comprising an inductor and a capacitor, the harmonic oscillator adapted to provide a first reference signal having a first frequency; a first plurality of controlled reactance modules coupled to the reference harmonic oscillator, each reactance module of the first plurality of reactance modules adapted to provide a selected reactance in response to a control voltage to maintain the first frequency substantially constant in a first operating mode; a first coefficient register adapted to store a first plurality of switching coefficients; a first plurality of switches coupled to the first plurality of controlled reactance modules, each switch of the first plurality of switches responsive to a corresponding switching coefficient of the first plurality of switching coefficients to couple a control voltage to a corresponding controlled reactance module; and a first divider coupled to the reference harmonic oscillator, the first divider adapted to provide a second reference signal at a second frequency. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48)
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49. A configurable integrated circuit comprising:
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a reference oscillator comprising an inductor, a capacitor, and an amplifier, the reference oscillator adapted to provide a first reference signal having a first frequency without locking to an external reference signal; a voltage controller adapted to provide a control voltage; a first plurality of controlled reactance modules coupled to the reference oscillator and to the voltage controller, each reactance module of the plurality of reactance modules adapted to provide a selected reactance in response to the control voltage to maintain the first frequency substantially constant in a first operating mode; a first divider coupled to the reference oscillator, the first divider adapted to provide a second reference signal at a second frequency; and a locking circuit coupled to the first divider, the locking circuit adapted to lock to the second reference signal and provide a third reference signal having a third frequency determined from the second frequency and a divide ratio of the locking circuit. - View Dependent Claims (50, 51, 52, 53)
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Specification