Clock control circuit and clock control method
First Claim
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1. A clock control circuit comprising:
- a frequency multiplying interpolator, which includes a plurality of circuits each of which is for outputting a signal obtained by internally dividing a phase difference between two signals, for generating a plurality of frequency-multiplied clocks, which have phases that differ from one another, from an input clock; and
at least one phase adjusting interpolator, to which are input two clocks from among the plurality of frequency-multiplied clocks of different phases output from said frequency multiplying interpolator, for outputting a signal obtained by internally dividing a phase difference between these two clocks.
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Abstract
A clock control circuit which includes a frequency multiplying interpolator for generating and outputting multiphase clocks by frequency multiplying an input clock; a switch for outputting two of the multiphase clocks input thereto from the frequency multiplying interpolator; a fine adjusting interpolator, to which the two outputs from the switch are applied, for outputting a signal obtained by internally dividing the phase difference between the two outputs; and a control circuit for controlling the switching of the switch and varying the internal-division ratio of the fine adjusting interpolator.
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Citations
44 Claims
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1. A clock control circuit comprising:
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a frequency multiplying interpolator, which includes a plurality of circuits each of which is for outputting a signal obtained by internally dividing a phase difference between two signals, for generating a plurality of frequency-multiplied clocks, which have phases that differ from one another, from an input clock; and
at least one phase adjusting interpolator, to which are input two clocks from among the plurality of frequency-multiplied clocks of different phases output from said frequency multiplying interpolator, for outputting a signal obtained by internally dividing a phase difference between these two clocks. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 40, 42, 43, 44)
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2. A clock control circuit comprising:
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(a) a frequency multiplying interpolator, which includes a plurality of circuits each of which is for outputting a signal obtained by internally dividing a phase difference between two signals, for generating multiphase clocks obtained by frequency multiplying an input clock;
(b) a switch, to which the multiphase clocks output from said frequency multiplying interpolator are input, for selectively outputting at least a pair of clocks from among the multiphase clocks;
(c) at least one phase adjusting interpolator, to which the pair of clocks output from said switch is input, for outputting a signal obtained by internally dividing a phase difference between the pair of clocks; and
(d) a control circuit for controlling a setting of an internal-division ratio of said phase adjusting interpolator and switching of a clock output by said switch. - View Dependent Claims (16, 17, 18, 19, 20)
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3. A clock control circuit comprising:
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(a) a frequency multiplying interpolator, which includes a plurality of circuits each of which is for outputting a signal obtained by internally dividing a phase difference between two signals, for generating multiphase clocks obtained by frequency multiplying an input clock;
(b) one or a plurality of switches, to which the multiphase clocks output from said frequency multiplying interpolator are input, for outputting pairs of clocks of combinations selected from among the multiphase clocks;
(c) a plurality of phase adjusting interpolators, to respective ones of which the plurality of pairs of clocks selectively output from said switch are input, for outputting signals obtained by internally dividing a phase difference between each pair of clocks; and
(d) a control circuit for controlling a setting of an internal-division ratio of each of said phase adjusting interpolators and switching of a clock output by said switch.
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21. An interpolator comprising:
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a logic circuit, to which first and second input signals are applied, for outputting result of a predetermined logical operation between the first and second input signals;
a first switch element connected between a first power supply and an internal node and having an output signal of said logic circuit input to a control terminal thereof; and
a buffer circuit having an input terminal connected to the internal node for inverting an output logic value if a size relationship between potential of the internal node and a threshold value reverses;
a plurality of series circuits being connected in parallel between the internal node and a second power supply, each of said series circuits comprising a first constant-current source, a second switch element turned on and off by the first input signal and a third switch element turned on and off by a control signal applied to a control terminal thereof;
a plurality of series circuits being connected in parallel between the internal node and the second power supply, each of said series circuits comprising a second constant-current source, a fourth switch element turned on and off by the second input signal and a fifth switch element turned on and off by a control signal applied to a control terminal thereof;
a plurality of series circuits being connected in parallel between the internal node and the second power supply, each of said series circuits comprising a sixth switch element and a capacitor;
capacitance applied to the internal node being decided by turning on and off the sixth switch element by a cycle control signal applied to a control terminal thereof;
an output signal corresponding to a phase obtained by internally dividing a phase difference between the first input signal and the second input signal being delivered from said buffer circuit in dependence upon a combination of values of the control signals applied to the control terminals of said third switch elements and to the control terminals of said fifth switch elements. - View Dependent Claims (22)
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23. A clock control method comprising the steps of:
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reducing jitter of a frequency-multiplied clock by generating multiphase clocks, which are obtained by frequency multiplying an input clock, using a frequency multiplying interpolator which includes a plurality of circuits each of which is for outputting a signal obtained by internally dividing a phase difference between two signals;
selecting two of the multiphase clocks, which are output from the frequency multiplying interpolator, by a switch and supplying the two clocks to a phase adjusting interpolator;
outputting from said phase adjusting interpolator a clock obtained by internally dividing a phase difference between the two clocks; and
performing control to vary an internal-division ratio of the phase adjusting interpolator based upon result of a phase comparison between a predetermined reference clock and an output clock of the phase adjusting interpolator.
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24. A clock control method using first, second and third interpolators each of which outputs a signal obtained by internally dividing a phase difference between two signals input thereto, said method comprising the steps of:
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inputting a common data signal, which is transferred in sync with a clock signal, to said first interpolator for delaying the data signal and then outputting the same;
inputting the clock signal to said second interpolator for outputting a clock signal obtained by internally dividing a timing difference between a leading edge and a trailing edge of a clock pulse;
inputting the clock signal to said third interpolator for outputting a clock signal obtained by internally dividing a timing difference between a trailing edge of the clock pulse and a leading edge of an ensuing clock pulse; and
latching data that is output from said first interpolator using a clock, which is obtained by multiplexing output signals from said second and third interpolators, as a latch timing pulse, and automatically adjusting latch timing to an optimum position with respect to the data independently of a fluctuation in duty of the clock signal.
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25. A clock control circuit comprising:
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a multiphase clock generating circuit for generating and outputting multiphase clocks from an input clock or generating and outputting multiphase clocks by frequency multiplying the input clock;
a plurality of switches, to which the multiphase clocks output from said frequency multiplying interpolator are input, for selecting and outputting pairs of clocks;
a plurality of interpolators, to respective ones of which the pairs of clocks output from said switch are input, for outputting signals obtained by internally dividing a phase difference between respective ones of the pairs of clocks; and
a control circuit for controlling a setting of an internal-division ratio of each of said interpolators and switching of a clock output by each of said switches;
a clock output from one of said interpolators being adjusted in phase so as to have a predetermined phase difference with respect to the input clock, and clocks output from the other of said interpolators being adjusted in phase so as to have a predetermined phase difference with respect to the input clock or with respect to an output clock of Yet another interpolator.
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26. A clock control circuit comprising:
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a multiphase clock generating circuit for generating and outputting multiphase clocks from an input clock or generating and outputting multiphase clocks by frequency multiplying the input clock;
first and second switches, to which the multiphase clocks output from said frequency multiplying interpolator are input for selecting and outputting pairs of clocks;
a first interpolator, to which the pair of clocks output from said first switch is input, for outputting a clock signal obtained by internally dividing a phase difference between the pair of clocks and applying a phase adjustment;
a second interpolator, to which the pair of clocks output from said second switch is input, for outputting a clock signal obtained by internally dividing a phase difference between the pair of clocks and applying a phase adjustment;
a phase comparator circuit for detecting a phase difference between an output of said first interpolator and the input clock;
a filter for smoothing a signal representing the result of the phase comparison output from said phase comparator circuit;
a first counter for counting up and counting down based upon the signal representing the result of the phase comparison output from said filter; and
a second counter, which is set to an offset value, for counting up and counting down based upon the signal representing the result of the phase comparison output from said filter;
setting of an internal-division ratio of said first interpolator and switching of a clock output by said first switch being performed based upon an output from said first counter; and
setting of an internal-division ratio of said second interpolator and switching of a clock output by said second switch being performed based upon an output from said second counter. - View Dependent Claims (30, 33, 34, 35, 36, 37, 38)
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27. A clock control circuit comprising:
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a multiphase clock generating circuit for generating and outputting multiphase clocks from an input clock or generating and outputting multiphase clocks by frequency multiplying the input clock;
first and second switches, to which the multiphase clocks output from said frequency multiplying interpolator are input, for selecting and outputting pairs of clocks;
a first interpolator, to which the pair of clocks output from said first switch is input, for outputting a clock signal obtained by internally dividing a phase difference between the pair of clocks and applying a phase adjustment;
a second interpolator, to which the pair of clocks output from said second switch is input, for outputting a clock signal obtained by internally dividing a phase difference between the pair of clocks and applying a phase adjustment;
said second interpolator having an output to which is connected a clock transmission path supplied with a clock;
said first interpolator having an output to which is connected a dummy circuit having a delay time equivalent to that of said clock transmission path;
a phase comparator circuit for detecting a phase difference between an output of said dummy circuit and the input clock;
a filter for smoothing a signal representing the result of the phase comparison output from said phase comparator circuit;
a first counter for counting up and counting down based upon the signal representing the result of the phase comparison output from said filter;
a first decoder for decoding an output count from said first counter;
an adder circuit for adding the output count from said first counter and an input offset value; and
a second decoder for decoding an output from said adder circuit;
setting of an internal-division ratio of said first interpolator and switching of a clock output by said first switch being performed based upon an output from said first decoder; and
setting of an internal-division ratio of said second interpolator and switching of a clock output by said second switch being performed based upon an output from said second decoder.
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28. A clock control circuit comprising:
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a multiphase clock generating circuit for generating and outputting multiphase clocks from an input clock or generating and outputting multiphase clocks by frequency multiplying the input clock;
first, second and third switches, to which the multiphase clocks output from said frequency multiplying interpolator are input, for selecting and outputting pairs of clocks;
first, second and third interpolators, to which the pairs of clocks output from said first, second and third switches, respectively, are input, for outputting clock signals obtained by internally dividing a phase difference between respective ones of the pairs of clocks and applying a phase adjustment;
said third interpolator having an output to which is connected a clock transmission path supplied with a clock;
a first phase comparator circuit for detecting a phase difference between an output of said first interpolator and the input clock;
a first filter for smoothing a signal representing the result of the phase comparison output from said first phase comparator circuit;
a first counter for counting up and counting down based upon the signal representing the result of the phase comparison output from said first filter;
a first decoder for decoding an output count from said first counter;
an adder circuit for adding the output count from said first counter and an input offset value;
a second decoder for decoding an output from said adder circuit;
setting of an internal-division ratio of said first interpolator and switching of a clock output by said first switch being performed based upon a decoded output from said first decoder;
setting of an internal-division ratio of said second interpolator and switching of a clock output by said second switch being performed based upon a decoded output from said second decoder;
a second phase comparator circuit for detecting a phase difference between an output of said clock transmission path and the output of said second interpolator;
a second filter for smoothing a signal representing the result of the phase comparison output from said second phase comparator circuit;
a second counter for counting up and counting down based upon the signal representing the result of the phase comparison output from said second filter; and
a third decoder for decoding an output count from said second counter;
setting of an internal-division ratio of said third interpolator and switching of a clock output by said third switch being performed based upon a decoded output from said third decoder. - View Dependent Claims (31)
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29. A clock control circuit comprising:
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a multiphase clock generating circuit for generating and outputting multiphase clocks from an input clock or generating and outputting multiphase clocks by frequency multiplying the input clock;
first, second, third and fourth switches, to which the multiphase clocks output from said frequency multiplying interpolator are input, for selecting and outputting pairs of clocks;
first, second, third and fourth interpolators, to which the pairs of clocks output from said first, second, third and fourth switches, respectively, are input, for outputting clock signals obtained by internally dividing a phase difference between respective ones of the pairs of clocks and applying a phase adjustment;
said fourth interpolator having an output to which is connected a clock transmission path supplied with a clock;
a first phase comparator circuit for detecting a phase difference between the rising edge of an output of said first interpolator and the rising edge of the input clock;
a first filter for smoothing a signal representing the result of the phase comparison output from said first phase comparator circuit;
a first counter for counting up and counting down based upon the signal representing the result of the phase comparison output from said first filter;
a second phase comparator circuit for detecting a phase difference between an output of said clock transmission path and the falling edge of a signal obtained by inverting the input clock by an inverting circuit;
a second filter for smoothing a signal representing the result of the phase comparison output from said second phase comparator circuit;
a second counter for counting up and counting down based upon the signal representing the result of the phase comparison output from said second filter;
an averaging circuit for averaging an output count from said first counter and an output count of said second counter;
a first decoder for decoding an output from said first counter;
a second decoder for decoding an output from said second counter;
a third decoder for decoding an output from said averaging circuit;
setting of an internal-division ratio of each of said first to third interpolators and switching of a clock output by each of said first to third switches being performed based upon a decoded output from each of said first to third decoders;
a third phase comparator circuit for detecting a phase difference between an output of said clock transmission path and the output of said third interpolator;
a third filter for smoothing a signal representing the result of the phase comparison output from said third phase comparator circuit;
a third counter for counting up and counting down based upon the signal representing the result of the phase comparison output from said third filter; and
a fourth decoder for decoding an output count from said third counter;
setting of an internal-division ratio of said fourth interpolator and switching of a clock output by said fourth switch being performed based upon a decoded output from said fourth decoder. - View Dependent Claims (32)
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39. A clock control circuit comprising:
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first, second and third interpolators each of which is for outputting a signal obtained by internally dividing a phase difference between two signals input thereto;
a common data signal being input to said first interpolator for being delayed and then output thereby;
a clock signal being input to said second interpolator, and said second interpolator outputting a clock signal obtained by internally dividing a timing difference between a leading edge and a trailing edge of a clock pulse;
said third interpolator outputting a clock signal obtained by internally dividing a timing difference between a trailing edge of the clock pulse and a leading edge of an ensuing clock pulse of the clock signal; and
a multiplexing circuit for multiplexing the output clocks from said second and third interpolators and outputting a clock signal;
the clock signal output from said multiplexing circuit being supplied to a latch circuit as a latch timing clock for latching data that is output from said first interpolator.
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41. A semiconductor integrated circuit device having a plurality of macroblocks, said device comprising:
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a frequency multiplying interpolator, which includes a plurality of circuits each of which is for outputting a signal obtained by internally dividing a phase difference between two signals, for generating and outputting multiphase clocks obtained by frequency multiplying an input clock;
each of said macroblocks having a switch, to which the multiphase clocks output from said frequency multiplying interpolator are input, for outputting at least two clocks from among the multiphase clocks, and a phase adjusting interpolator, to which an output from said switch is input, for outputting a signal obtained by internally dividing the phase of said output; and
a control circuit for controlling switching of the clock by said switch and varying an internal-division ratio of said phase adjusting interpolator.
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Specification