High speed voltage-controlled ring oscillator
First Claim
1. A voltage-controlled ring oscillator comprising:
- a plurality of interpolation stages having two signal inputs and a signal output, each of said stages receiving a first signal input comprising an output from an immediate previous stage (X) and a second signal input comprising an output from a previous stage (X−
1); and
each of said stages adapted to receive first and second control voltages.
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Accused Products
Abstract
A high speed ring voltage-controlled oscillator (VCO) system is provided. The ring VCO system includes a plurality of interpolation stages coupled in a “look-ahead” configuration. Each interpolation stage receives two signal inputs and outputs a single differential voltage representative of a time delay interpolation between the two input signals. In accordance with the invention, each interpolation stage receives a first signal input from the immediately previous stage and a second signal input from the output of a different stage. In this manner, the delay stages in the ring VCO can generate a variable delay by interpolating between inputs with small relative delays without adding additional delay to the total loop delay.
11 Citations
42 Claims
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1. A voltage-controlled ring oscillator comprising:
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a plurality of interpolation stages having two signal inputs and a signal output, each of said stages receiving a first signal input comprising an output from an immediate previous stage (X) and a second signal input comprising an output from a previous stage (X−
1); and
each of said stages adapted to receive first and second control voltages. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A delay interpolation voltage-controlled oscillator (VCO) comprising:
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a plurality of analog summers coupled in a look-ahead interpolation configuration comprising;
a first analog summer having a first input (A) and a second input (B) and an output (C);
a second analog summer having a first input (B) and a second input (C) and an output (D);
a third analog summer having a first input (C) and a second input (D) and an output (A);
a fourth analog summer having a first input (D) and a second input (A) and an output (B), whereby, each of said analog summers outputs is electrically coupled as inputs to the other analog summers; and
at least two control voltages supplied to each of said plurality of analog summers. - View Dependent Claims (12, 13, 14, 15)
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16. A voltage-controlled ring oscillator comprising:
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a plurality of interpolation stages coupled in a look-ahead interpolation architecture such that each of said stages includes a first and second signal input and a signal output, said first signal input comprising an output from an immediate previous stage (X) and said second signal input comprising an output from a previous stage (X−
1), one of said signal inputs being weight limited to less than 100%; and
at least two control voltages supplied to each of said stages. - View Dependent Claims (17, 18, 19, 20)
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21. A method for signal interpolation in a voltage-controlled oscillator (VCO) comprising a plurality of interpolation stages, said method comprising the steps of:
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applying a first control voltage to an interpolation stage (N) of said plurality of interpolation stages;
applying a second control voltage to an interpolation stage (N) of said plurality of interpolation stages;
applying a first signal input to said stage (N) such that said first signal comprises an output of a stage (N−
1);
applying a second signal input to said stage (N) such that said second signal comprises an output of a stag (N−
2);
using analog summation, determining a voltage representation of a time delay between said first and second signal;
outputting said voltage representation from said stage (N); and
repeating said method steps for each of said stages in said VCO. - View Dependent Claims (22, 23, 24, 25, 26)
applying a differential voltage to a voltage-to-current (V-I) translator;
outputting two differential voltages from said (V-I) translator; and
applying said two differential voltages to two control inputs of said stage.
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25. The method for signal interpolation of claim 24, further comprising the step of generating two differential voltages such that when applied to said two control inputs of said stage, a substantially constant current is received.
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26. The method for signal interpolation of claim 24, wherein said step of applying a control voltage further comprises the step of applying a control voltage to a third control input such that a substantially fixed current is received.
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27. A voltage-controlled ring oscillator comprising:
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a plurality of interpolation stages having two signal inputs and a signal output, each of said stages receiving a first signal input comprising an output from an immediate previous stage (X) and a second signal input comprising an output from a previous stage (X−
1);
a control voltage supplied to each of said stages; and
a voltage-to-current (V-I) translator in electrical communication with each of said stages. - View Dependent Claims (28, 31, 32, 33)
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29. A voltage-controlled ring oscillator comprising:
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a plurality of interpolation stages having two signal inputs and a signal output, each of said stages receiving a first signal input comprising an output from an immediate previous stage (X) and a second signal input comprising an output from a previous stage (X−
1);
a control voltage supplied to each of said stages;
wherein each of said stages comprises an analog summer; and
a voltage-to-current (V-I) translator in electrical communication with each of said analog summers and providing a substantially constant voltage to said analog summers. - View Dependent Claims (30)
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34. A delay interpolation voltage-controlled oscillator (VCO) comprising:
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a plurality of analog summers coupled in a look-ahead interpolation configuration comprising;
a first analog summer having a first input (A) and a second input (B) and an output (C);
a second analog summer having a first input (B) and a second input (C) and an output (D);
a third analog summer having a first input (C) and a second input (D) and an output (A);
a fourth analog summer having a first input (D) and a second input (A) and an output (B), whereby, each of said analog summers outputs is electrically coupled as inputs to the other analog summers; and
a control voltage supplied to said plurality of analog summers;
wherein a weight of one of said inputs to at least one of said analog summers is limited; and
said weight limited input is 80%.
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35. A delay interpolation voltage-controlled oscillator (VCO) comprising:
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a plurality of analog summers coupled in a look-ahead interpolation configuration comprising;
a first analog summer having a first input (A) and a second input (B) and an output (C);
a second analog summer having a first input (B) and a second input (C) and an output (D);
a third analog summer having a first input (C) and a second input (D) and an output (A);
a fourth analog summer having a first input (D) and a second input (A) and an output (B), whereby, each of said analog summers outputs is electrically coupled as inputs to the other analog summers;
a control voltage supplied to said plurality of analog summers; and
a voltage to current translator providing a constant voltage to said plurality of analog summers.
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36. A voltage-controlled ring oscillator comprising:
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a plurality of interpolation stages coupled in a look-ahead interpolation architecture such that each of said stages includes a first and second signal input and a signal output, said first signal input comprising an output from an immediate previous stage (X) and said second signal input comprising an output from a previous stage (X−
1), one of said signal inputs being weight limited to less than 100%; and
a control voltage supplied to each of said stages;
wherein said weight limited input comprises 80%.
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37. A voltage-controlled ring oscillator comprising:
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a plurality of interpolation stages coupled in a look-ahead interpolation architecture such that each of said stages includes a first and second signal input and a signal output, said first signal input comprising an output from an immediate previous stage (X) and said second signal input comprising an output from a previous stage (X−
1), one of said signal inputs being weight limited to less than 100%;
a control voltage supplied to each of said stages; and
a voltage-to-current (V-I) translator in electrical communication with each of said stages. - View Dependent Claims (38)
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39. A method for signal interpolation in a voltage-controlled oscillator (VCO) comprising a plurality of interpolation stages, said method comprising the steps of:
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applying a control voltage to an interpolation stage (N) of said plurality of interpolation stages;
applying a first signal input to said stage (N) such that said first signal comprises an output of a stage (N−
1);
applying a second signal input to said stage (N) such that said second signal comprises an output of a stage (N−
2);
using analog summation, determining a voltage representation of a time delay between said first and second signal;
outputting said voltage representation from said stage (N);
repeating said method steps for each of said stages in said VCO; and
weight limiting one of said first or second signal inputs;
wherein said weight limiting step comprises limiting to 80%.
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40. A method for signal interpolation in a voltage-controlled oscillator (VCO) comprising a plurality of interpolation stages, said method comprising the steps of:
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applying a control voltage to an interpolation stage (N) of said plurality of interpolation stages;
applying a first signal input to said stage (N) such that said first signal comprises an output of a stage (N−
1);
applying a second signal input to said stage (N) such that said second signal comprises an output of a stage (N−
2);
using analog summation, determining a voltage representation of a time delay between said first and second signal;
outputting said voltage representation from said stage (N); and
repeating said method steps for each of said stages in said VCO;
wherein said step of applying a control voltage comprises the steps of;
applying a differential voltage to a voltage-to-current (V-I) translator;
outputting two differential voltages from said (V-I) translator; and
applying said two differential voltages to two control inputs of said stage. - View Dependent Claims (41, 42)
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Specification