Method for reducing static phase offset in a PLL
First Claim
1. An architecture comprising:
- a) a first chase frequency detector that outputs a first active operating signal in response to one or more reference signals;
b) a first charge pump circuit configured to provide a replica pump signal in response to (I) a current adjustment signal and (II) either (i) at least one of said one or more reference signals or (ii) said first active operating signal;
c) a second charge pump circuit configured to provide a voltage control signal in response to said current adjustment signal and either said first active operating signal or a second, independent active operating signal; and
d) a comparator configured to provide said current adjustment signal in response to said replica pump signal and said voltage control signal.
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Accused Products
Abstract
An architecture comprising a detector, a first pump circuit, a second pump circuit and a comparator. The detector may present a first active operating signal in response to one or more reference signals. In one example, the first active operating signal may be generated in response to a feedback signal having a parameter within a predetermined range. The first pump circuit may be configured to provide a replica pump signal in response to a current adjustment signal and either (i) at least one of the one or more reference signals or (ii) the first active operating signal. The second pump circuit may be configured to provide a voltage control signal in response to the current adjustment signal and either (i) the first active operating signal or (ii) a second, independent active operating signal. The comparator may be configured to provide the current adjustment signal in response to the replica pump signal and the voltage control signal.
113 Citations
14 Claims
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1. An architecture comprising:
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a) a first chase frequency detector that outputs a first active operating signal in response to one or more reference signals;
b) a first charge pump circuit configured to provide a replica pump signal in response to (I) a current adjustment signal and (II) either (i) at least one of said one or more reference signals or (ii) said first active operating signal;
c) a second charge pump circuit configured to provide a voltage control signal in response to said current adjustment signal and either said first active operating signal or a second, independent active operating signal; and
d) a comparator configured to provide said current adjustment signal in response to said replica pump signal and said voltage control signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
a) a second phase frequency detector that outputs a second active operating signal in response to a second reference signal and a feedback signal.
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3. The architecture according to claim 2, wherein said architecture further comprises one or more of the following:
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b) a first filter coupled to said first charge pump circuit and said comparator, configured to filter said replica pump signal; and
c) a second filter coupled to said second charge pump circuit, said comparator and an oscillator, configured to filter said voltage control signal.
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4. The architecture of claim 3, wherein said oscillator is configured to provide a periodically oscillating signal in response to said voltage control signal.
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5. The architecture of claim 4, wherein said periodically oscillating signal is also said feedback signal.
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6. The architecture of claim 4, wherein said architecture provides at least one function selected from the group consisting of (i) reducing static phase offset in said oscillator, and (ii) reducing effects on said periodically oscillating signal of variations in one or more parameters selected from the group consisting of manufacturing and/or process conditions, operating temperature, operating voltage, and output voltage.
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7. The architecture according to claim 1, wherein said first active operating signal is generated in response to a feedback signal having a parameter within a predetermined range.
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8. A circuit comprising:
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a) a first charge pump circuit configured to provide a feedback adjustment signal in response to (i) a current adjustment signal and (ii) one or more reference signals or one or more pump control signals; and
b) a comparator configured to provide said current adjustment signal to both said first charge pump circuit and a second charge pump circuit providing an input to an oscillator in response to said feedback adjustment signal and a voltage control signal from said second pump circuit. - View Dependent Claims (9, 10, 11, 12)
a) said first charge pump circuit provides said feedback adjustment signal in response to (i) said current adjustment signal, (ii) a first pump control signal to increase current flow to the comparator, and (iii) a second pump control signal to decrease current flow to the comparator; and
b) said circuit further comprises a phase frequency detector that outputs said first and second pump control signals in response to one or more reference signals.
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10. The circuit of claim 9, wherein said first charge pump circuit comprises (i) a first pump control circuit configured to increase current flow to the comparator in response to the first pump control signal, and (ii) a second pump control circuit configured to decrease current flow to the comparator in response to the second pump control signal;
- and (iii) a current adjustment circuit configured to adjust the current output of at least one of said first and second pump control circuits in response to said current adjustment signal.
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11. The circuit of claim 10, further comprising a filter coupled to said first charge pump circuit and said comparator.
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12. The circuit of claim 8, wherein said circuit provides at least one function selected from the group consisting of (i) reducing static phase offset in said oscillator, and (ii) reducing effects of variations in one or more parameters selected from the group consisting of (a) manufacturing and/or process conditions, (b) operating temperature, (c) operating voltage, and (d) output voltage, on a periodically oscillating signal generated by said oscillator.
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13. A method of reducing static phase offset in an oscillator comprising the steps of:
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a) comparing current outputs of essentially identical first and second charge pump circuits, and b) adjusting the current output of at least one of said first and second charge pump circuits in response thereto, wherein at least one of said first and second charge pump circuits provides an input to said oscillator. - View Dependent Claims (14)
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Specification