Power saving circuitry using predictive logic
First Claim
1. A method of performing a time-to-digital conversion between edges of a first signal and a second signal, wherein said first signal transitions between states rapidly with respect to said second signal, comprising the steps of:
- passing said first signal to a string of logic devices during a time period sufficient to allow the first circuit to reach a desired state prior to an active edge of the second signal and not passing the first signal to the string of logic devices during other time periods;
storing a state associated with said string of logic devices responsive to the active edge of the second signal.
1 Assignment
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Accused Products
Abstract
To conserve power in a circuit where a high-speed signal HSIG controls combinational logic (10), while a low-speed signal LCLK drives a logic/memory circuit (12) that samples the output of the combinational logic, predictive logic state machine (14) generates a clock, P_LCLK, which has an active level preceding the active edge of LCLK by a period sufficient to allow the combinational logic to reach the desired state prior to the active edge of LCLK and, preferably, allows for possible jitter in LCLK. Responsive to P_LCLK, the signal suspend circuitry (16) either passes HSIG or gates off HSIG. Further reductions in power can be accomplished by predicting which portions of the logic/memory circuit (12) will be used, and clocking those portions.
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Citations
35 Claims
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1. A method of performing a time-to-digital conversion between edges of a first signal and a second signal, wherein said first signal transitions between states rapidly with respect to said second signal, comprising the steps of:
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passing said first signal to a string of logic devices during a time period sufficient to allow the first circuit to reach a desired state prior to an active edge of the second signal and not passing the first signal to the string of logic devices during other time periods;
storing a state associated with said string of logic devices responsive to the active edge of the second signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of performing a time-to-digital conversion between edges of a first signal and a second signal, wherein said first signal transitions between states rapidly with respect to said second signal, comprising the steps of:
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passing said first signal to a string of logic devices during a time period sufficient to allow the string logic devices to reach the desired state prior to an active edge of the second signal and not passing the first signal to the string of logic devices during other time periods; and
storing a state, associated with said string of selected logic devices responsive to the active edge of the second signal, in a set of respective storage devices coupled to outputs of said logic devices, at the active edge of said second signal, said set of respective storage devices being selected based on a prediction of a propagation of an edge of said first signal through said string of logic devices at the active edge of said second signal.
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9. A time-to-digital converter, comprising:
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circuitry for receiving a first signal;
circuitry for receiving a second signal, wherein said first signal transitions between states rapidly with respect to said second signal;
a string of logic devices responsive to state transitions of said first signal;
circuitry for determining a time difference between one or more edges of said first signal relative to an active edge of said second signal responsive to a state associated with said string of logic devices at the active edge of a second signal; and
circuitry for preventing state transitions of said first signal causing transitions in said string of logic devices during periods between active edges of said second signal. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A time-to-digital converter, comprising:
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circuitry for receiving a first signal;
circuitry for receiving a second signal, wherein said first signal transitions between states rapidly with respect to said second signal;
a string of logic devices responsive to state transitions of said first signal;
circuitry for determining a time difference between one or more edges of said first signal relative to an active edge of said second signal responsive to a state associated with said string of logic devices at the active edge of a second signal; and
circuitry for preventing state transitions of said first signal causing transitions in said string of logic devices during periods between active edges of said second signal and for passing said first signal to said second signal responsive to said time period. - View Dependent Claims (17)
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18. A method of conserving energy in a circuit comprising a first circuit of combination logic and a second circuit, wherein said first circuit is responsive to a first signal and said second circuit is responsive to a state of said first circuit at an active edge of the second signal, wherein said first signal transitions between states rapidly with respect to said second signal, comprising the steps of:
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passing the first signal to the first circuit during a time period sufficient to allow the first circuit to reach a desired state prior to the active edge of the second signal and not passing the first signal to the first circuit during other time periods; and
using state information from said first circuit in said second circuit responsive to the active edge of the second signal.
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19. A method of conserving energy in a circuit comprising a first circuit of combination logic and a second circuit, wherein said first circuit is responsive to a first signal and second circuit is responsive to a state of said first circuit at an active edge of the second signal, wherein said first signal transition between states rapidly with respect to said second signal, comprising the steps of:
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passing the first signal to the first circuit during a time period sufficient to allow the first circuit to reach a desired state prior to the active edge of the second signal and not passing the first signal to the first circuit during other time periods;
using state information from said first circuit in said second circuit responsive to the active edge of the second signal; and
predicting which portions of said second circuit will be used.
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20. A method of performing a time-to-digital conversion between edges of a first signal and a second signal, wherein said first signal transitions between states rapidly with respect to said second signal, comprising the steps of:
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passing said first signal to a string of logic devices;
predicting a location of a transition of said first signal as propagated through said string of logic devices;
storing a state associated with a predetermined set of said string of logic devices around said predicted location responsive to the active edge of the second signal. - View Dependent Claims (21, 22, 23, 24)
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25. Circuitry for performing a time-to-digital conversion between edges of a first signal and a second signal, wherein said first signal transitions between states rapidly with respect to said second signal, comprising:
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a string of logic devices through which a first signal is propagated;
circuitry predicting a location of a transition of said first signal as propagated through said string of logic devices;
storage circuits for storing output states of respective logic devices; and
circuitry for enabling a predetermined set of said storage circuits associated with logic devices around said predicted location responsive to the active edge of the second signal.- View Dependent Claims (26, 27, 28, 29)
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30. A method, comprising the steps of:
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performing a time-to-digital conversion between edges of a first signal and a second signal, wherein said first signal transitions between states rapidly with respect to said second signal; and
passing said first signal to a string of logic devices in a circuit during a time period sufficient to allow the circuit to each a desired state prior to an active edge of the second signal and not passing the first signal to the string of logic devices during other time periods. - View Dependent Claims (31, 33)
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32. A method, comprising the steps of:
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performing a time-to-digital conversion between edges of a first signal and a second signal, wherein said first signal transition between states rapidly with respect to said second signal;
passing said first signal to a string of logic devices in a circuit during a time period sufficient to allow the circuit to reach a desired state prior to an active edge of second signal and not passing the first signal to the string of logic devices during other time period and predicting a time period within which a next occurrence of an active edge of said second signal will occur.
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34. A telecommunication device, comprising:
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a baseband controller; and
a transceiver coupled to d baseband controller, said transceiver further comprising circuitry for performing a time-to-digital conversion between edges of a first signal and a second signal, wherein said first signal transitions between states rapidly with respect to said second signal, comprising;
a string of logic devices through which a first signal is propagated;
circuitry predicting location of a transition of said first signal as propagated through said string of logic devices;
storage circuits for string output states of respective logic devices; and
circuitry for enabling a predetermined set of said storage circuits associated with logic devices around said predicted location responsive to the active edge of the second signal.
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35. A telecommunication device, comprising:
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a baseband controller;
ana transceiver coupled to said baseband controller, said transceiver further comprising a time-to-digital converter, comprising;
circuitry for receiving a first signal;
circuitry for receiving a second signal, wherein said first signal transitions between states rapidly with respect to said second signal;
a string of logic devices responsive to state transitions of said first signal;
circuitry for determining a time difference between one or more edges of said first signal relative to an active edge of said second signal responsive to a state associated with said string of logic devices at the active edge of a second signal; and
circuitry for preventing state transitions of said first signal causing transitions in said string of logic devices during periods between active edges of said second signal.
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Specification