Methods and apparatus for clock tree phase alignment
First Claim
1. Clock alignment circuitry comprising:
- phase comparator circuitry having a first input terminal that receives a first clock signal from a first clock tree and a second input terminal that receives a second clock signal from a second clock tree, wherein the phase comparator circuitry compares the first and second clock signals and outputs corresponding first and second control signals; and
phase interpolator circuitry that receives a third clock signal and that generates an output clock signal that is aligned with one of the first and second clock signals based on at least one of the first and second control signals, wherein the first clock signal comprises a loopback version of the third clock signal being routed through the first clock tree.
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Abstract
Clock alignment circuitry may include phase comparator circuitry with a first input terminal that receives as first clock signal from a first clock tree and a second input terminal that receives a second clock signal from a second clock tree. The phase comparator circuitry may compare the first and second clock signals and generate different control signals based on the first and second clock signals. The integrated circuit may further include phase interpolator circuitry that generates an output clock signal based on at least one of the control signals received from the phase comparator circuitry. Edges of the generated output clock signal may align with edges of either the first clock signal or the second clock signal.
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Citations
19 Claims
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1. Clock alignment circuitry comprising:
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phase comparator circuitry having a first input terminal that receives a first clock signal from a first clock tree and a second input terminal that receives a second clock signal from a second clock tree, wherein the phase comparator circuitry compares the first and second clock signals and outputs corresponding first and second control signals; and phase interpolator circuitry that receives a third clock signal and that generates an output clock signal that is aligned with one of the first and second clock signals based on at least one of the first and second control signals, wherein the first clock signal comprises a loopback version of the third clock signal being routed through the first clock tree. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. Clock alignment circuitry comprising:
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phase comparator circuitry that receives first and second feedback clock signals from first and second clock trees, respectively, wherein the phase comparator circuitry generates first and second control signals based on phases of the first and second feedback clock signals; and phase interpolator circuitry that receives the first and second control signals and that adjusts a phase of an output feedback clock signal based on at least one of the first and second control signals such that the phase of the output feedback clock signal is aligned with a phase of the first feedback clock signal, wherein the phase interpolator circuitry comprises; a first phase interpolator that receives first, second, and third phases of an input clock signal and that generates a corresponding first interpolated clock signal; and a second phase interpolator that receives fourth, fifth and sixth phases of the input clock signal and that generates a corresponding second interpolated clock signal, wherein the first, second, third, fourth, fifth, and sixth clock phases each have a different respective phase value, and wherein the first feedback clock signal comprises a feedback of the input clock signal. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A method of aligning clock signals in an integrated circuit, the method comprising:
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with phase comparator circuitry, comparing a first feedback clock signal received from a first clock tree with a second feedback clock signal received from a second clock tree; in response to comparison of the first and second feedback clock signals, generating first and second control signals with the phase comparator circuitry; and with interpolator circuitry, interpolating from a plurality of phases of a third clock signal based on at least one of the first and second control signals to generate an output clock signal, wherein the third clock signal is routed through the first clock tree to produce the first feedback clock signal. - View Dependent Claims (17, 18, 19)
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Specification