Digitally controlled oscillator circuit
First Claim
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1. An oscillator circuit, comprising:
- a phase comparator having first and second clock signal inputs, and outputs having predetermined relationships to characteristics of the first and second clock signals;
a ring oscillator circuit;
a first control means connected to a first output of the phase comparator for generating a first control current, the first control current having a value within a first range of control currents, the first control current being supplied to the ring oscillator, resulting in the adjustment of an output frequency of the ring oscillator circuit over a first frequency adjustment range, the first control means also providing as an output a first set of digital signals;
a second control means connected to an output of the first control means for generating a second control current, the second control current having a value within a second range of control currents, the second control current being supplied to the ring oscillator circuit, resulting in adjustment of the output frequency of the ring oscillator circuit over a second frequency adjustment range.
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Abstract
A variable frequency oscillator circuit includes a ring oscillator circuit, a plurality of adjustment means for adjusting an output frequency of the ring oscillator circuit, at least one of the adjustment means having monotonic behavior, adapted to switch between first adjustment levels at a first rate and at least one of the adjustment means having non-monotonic behavior, adapted to switch between second adjustment levels at a second rate which is less than the first rate, such that the means having monotonic behavior adjusts for monotonicity errors which occur during switching.
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Citations
16 Claims
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1. An oscillator circuit, comprising:
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a phase comparator having first and second clock signal inputs, and outputs having predetermined relationships to characteristics of the first and second clock signals; a ring oscillator circuit; a first control means connected to a first output of the phase comparator for generating a first control current, the first control current having a value within a first range of control currents, the first control current being supplied to the ring oscillator, resulting in the adjustment of an output frequency of the ring oscillator circuit over a first frequency adjustment range, the first control means also providing as an output a first set of digital signals; a second control means connected to an output of the first control means for generating a second control current, the second control current having a value within a second range of control currents, the second control current being supplied to the ring oscillator circuit, resulting in adjustment of the output frequency of the ring oscillator circuit over a second frequency adjustment range. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A semiconductor integrated circuit, comprising:
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a phase comparator having first and second clock signal inputs, and outputs having predetermined relationships to characteristics of the first and second clock signals; a ring oscillator circuit; a first control means connected to the output of the phase comparator for generating a first control current, the first control current having a value within a first range of control currents, the first control current being supplied to the ring oscillator, resulting in the adjustment of an output frequency of the ring oscillator circuit over a first frequency adjustment range, the first control means also providing as an output a first set of digital signals; a second control means connected to an output of the first control means for generating a second control current, the second control current having a value within a second range of control currents, the second control current being supplied to the ring oscillator circuit, resulting in adjustment of the output frequency of the ring oscillator circuit over a second frequency adjustment range. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A digitally controlled oscillator circuit, comprising:
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a ring oscillator circuit; a plurality of adjustment means for adjusting an output frequency of the ring oscillator circuit; at least one of the adjustment means having monotonic behavior, adapted to switch between first adjustment levels at a first rate and at least one of the adjustment means having non-monotonic behavior, adapted to switch between second adjustment levels at a second rate which is less than the first rate, such that the means having monotonic behavior adjusts for monotonicity errors which occur during switching, wherein the plurality of adjustment means further comprises; first and a second control circuits, the first control circuit generating a first control current, the first control current having a value within a first range of control currents, the first control current being supplied to the ring oscillator, resulting in the adjustment of an output frequency of the ring oscillator circuit over a first frequently adjustment range, the first control means also providing as an output a first set of digital signals; a second control means connected to an output of the first control means for generating a second control current, the second control current having a value within a second range of control currents, the second control current being supplied to the ring oscillator circuit, resulting in adjustment of the output frequency of the ring oscillator circuit over a second frequency adjustment range. - View Dependent Claims (14, 15, 16)
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Specification