Architecture of a PLL with dynamic frequency control on a PLD
First Claim
Patent Images
1. An apparatus comprising:
- a clock generating circuit configured to generate one or more output signals in response to a reference signal and one or more control signals, wherein said output signals each have a frequency and a phase that are dynamically variable;
a programmable logic circuit configured to generate one or more of said control signals and receive said one or more output signals; and
a plurality of tri-statable buffers coupling said output signals of said clock generating circuit to said programmable logic circuit, wherein said clock generating circuit is configured to (i) receive said one or more control signals (a) from an external source when in a first mode, (b) internally from said programmable logic circuit when in a second mode, and (c) from both said external source and internally from said programmable logic circuit when in a third mode and (ii) said tri-statable buffers are configured to present said output signals to said programmable logic circuit when said clock generating circuit is in a locked state.
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Abstract
An apparatus including a clock generating circuit and a programmable logic circuit. The clock generating circuit may be configured to generate one or more output signals in response to a reference signal and one or more control signals, wherein the output signals each have a frequency and a phase that are dynamically variable. The programmable logic circuit may be configured to generate one or more of the control signals and receive the one or more output signals.
131 Citations
18 Claims
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1. An apparatus comprising:
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a clock generating circuit configured to generate one or more output signals in response to a reference signal and one or more control signals, wherein said output signals each have a frequency and a phase that are dynamically variable;
a programmable logic circuit configured to generate one or more of said control signals and receive said one or more output signals; and
a plurality of tri-statable buffers coupling said output signals of said clock generating circuit to said programmable logic circuit, wherein said clock generating circuit is configured to (i) receive said one or more control signals (a) from an external source when in a first mode, (b) internally from said programmable logic circuit when in a second mode, and (c) from both said external source and internally from said programmable logic circuit when in a third mode and (ii) said tri-statable buffers are configured to present said output signals to said programmable logic circuit when said clock generating circuit is in a locked state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus comprising:
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means for generating one or more output signals in response to a reference signal and one or more control signals, wherein said output signals each having a frequency and a phase that is dynamically variable; and
means for implementing user defined logic configured to generate said one or more control signals and receive said one or more output signals, wherein said phase of said output signals is varied by selecting one of a plurality of phases from a multi-phase phase lock loop.
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11. A method for dynamically changing a frequency and/or phase of a clock signal on a programmable logic device comprising the steps of:
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(A) generating one or more output signals in response to a reference signal and one or more control signals, wherein said output signals each have a frequency and a phase that are dynamically variable;
(B) receiving said one or more of output signals; and
(C) generating one or more of said control signals in response to one or more predetermined logic expressions, wherein said phase of said output signals is varied by selecting one of a plurality of phases from a multi-phase phase lock loop. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
storing a default phase and frequency for said one or more output signals.
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13. The method according to claim 11, wherein the step (A) further comprises the sub-step of:
selecting a phase and/or frequency for one or more of said output signals that is different from said default value based on said one or more control signals.
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14. The method according to claim 13, wherein said output signals are enabled in response to a lock signal.
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15. The method according to claim 11, wherein the step (A) comprises the sub-steps of:
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disabling said one or more output signals;
changing said phase and/or frequency of one or more of said output signals; and
enabling said one or more output signals.
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16. The method according to claim 11, wherein said frequency of said output signals is varied by changing multiplier values of a phase lock loop.
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17. The method according to claim 11, wherein said frequency of said output signals is varied by changing a divider value.
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18. The method according to claim 11, wherein said phase of said output signals is varied by changing a delay value of a delay lock loop.
Specification