Multi-phase delay locked loop with equally-spaced phases over a wide frequency range and method thereof
First Claim
1. A Delay Locked Loop (DLL) with equally spaced phases over a wide frequency range, the DLL comprising:
- a delay line for receiving a reference clock signal and outputting a final delay clock signal in response to the reference clock signal, wherein the delay line includes a plurality of delay cells connected in series, the plurality of delay cells generating a plurality of delay clock signals having equally spaced phases;
a control module coupled to the delay line, for generating a phase control signal based on counting a number of pulses of the reference clock signal that are input to the delay line before occurrence of a first corresponding pulse of the final delay clock signal, the control module comprising;
a calibration module for generating a co-prime number with respect to the plurality of delay clock signals, wherein the co-prime number is generated based on counting the number of pulses of the reference clock signal, the calibration module comprising;
a counter for counting the number of pulses of the reference clock signal;
a decoder coupled to the counter, for generating the co-prime number by decoding a count of the number of pulses of the reference clock signal;
a masking module for masking edges of the reference clock signal and the final delay clock signal; and
a phase control module coupled to the calibration module, for generating the phase control signal based on a value of the co-prime number.
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Abstract
A Delay Locked Loop (DLL) and method for generating multiple equally spaced phases over a wide frequency range is disclosed. The DLL includes a delay line, and a control module. The delay line receives a reference clock signal and outputs a final delay clock signal in response to the reference clock signal. The delay line includes a plurality of delay cells connected in series. The plurality of delay cells generate a plurality of delay clock signals having equally spaced phases. The control module generates a phase control signal based on counting a number of pulses of the reference clock signal that are input to the delay line before occurrence of a first corresponding pulse of the final delay clock signal.
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Citations
13 Claims
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1. A Delay Locked Loop (DLL) with equally spaced phases over a wide frequency range, the DLL comprising:
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a delay line for receiving a reference clock signal and outputting a final delay clock signal in response to the reference clock signal, wherein the delay line includes a plurality of delay cells connected in series, the plurality of delay cells generating a plurality of delay clock signals having equally spaced phases; a control module coupled to the delay line, for generating a phase control signal based on counting a number of pulses of the reference clock signal that are input to the delay line before occurrence of a first corresponding pulse of the final delay clock signal, the control module comprising; a calibration module for generating a co-prime number with respect to the plurality of delay clock signals, wherein the co-prime number is generated based on counting the number of pulses of the reference clock signal, the calibration module comprising; a counter for counting the number of pulses of the reference clock signal; a decoder coupled to the counter, for generating the co-prime number by decoding a count of the number of pulses of the reference clock signal; a masking module for masking edges of the reference clock signal and the final delay clock signal; and a phase control module coupled to the calibration module, for generating the phase control signal based on a value of the co-prime number. - View Dependent Claims (2, 3, 4, 5)
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6. A Delay Locked Loop (DLL) with equally spaced phases over a wide frequency range, the DLL comprising:
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a calibration module that generates a number, wherein the number and a count of a delay clock signal for an interval of time are co-prime to each other; a phase control module responsive to a reference clock signal, the delay clock signal, and the number, and to generate a phase control signal based on a value of the number, the phase control module comprising; a divider module for dividing frequency of the reference clock signal and a final delay clock signal by the number; a Phase Frequency Detector (PFD) coupled to the divider module, for comparing phases of the reference clock signal and the final delay clock signal; and a charge pump coupled to the PFD, for generating the phase control signal based on comparing the phases of the reference clock signal and the final delay clock signal. - View Dependent Claims (7)
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8. A Delay Locked Loop (DLL) with equally spaced phases over a wide frequency range, wherein the DLL receives a reference clock signal and outputs a plurality of delay clock signals such that a phase difference between any two adjacent delay clock signals of the plurality of delay clock signals is equal, the plurality of delay clock signals including a final delay clock signal, the DLL comprising:
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a masking module for masking a pre-defined number of edges of the reference clock signal and the final delay clock signal, and generating a start_count signal and a stop_count signal upon masking the pre-defined number of edges of the reference clock signal and the final delay clock signal respectively; a counter coupled to the masking module, for generating a count of a number of pulses of the reference clock signal that are input to the delay line between inputting a pulse of the reference clock signal to the delay line and occurrence of a corresponding pulse of the final delay clock signal; a decoder coupled to the counter, for decoding the count to generate a co-prime number with respect to a number of delay clock signals in the plurality of delay clock signals; a divider module coupled to the decoder, for receiving a value of the co-prime number, and dividing frequencies of the reference clock signal and the final delay clock signal by the co-prime number to generate a reference phase signal and a delay phase signal respectively; a Phase Frequency Detector (PFD) coupled to the divider module, for comparing the reference phase signal and the delay phase signal in terms of phase; a charge pump coupled to the PFD, for generating a phase control signal based on comparing the reference phase signal and the delay phase signal; and a delay line coupled to the charge pump, wherein the delay line includes a plurality of delay cells connected in series, the plurality of delay cells generating the plurality of delay clock signals on receiving the phase control signal. - View Dependent Claims (9, 10)
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11. A method for generating a plurality of equal-spaced phases with a wide frequency range using a Delay Locked Loop (DLL), the DLL including a plurality of delay cells connected in series, the plurality of delay cells generating a plurality of delay clock signals in response to a reference clock signal, the plurality of delay clock signals including a final delay clock signal, the method comprising:
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generating a number, wherein the number and a count of a delay clock signal for an interval of time are co-prime to each other; dividing a frequency of the reference clock signal and the final delay clock signal by the number to generate a reference phase signal and a delay phase signal respectively; comparing phases of the reference phase signal and the delay phase signal; generating a phase control signal based on comparing the phases; and controlling a phase difference between any two adjacent delay clock signals of the plurality of delay clock signals through the phase control signal for generating the plurality of equal-spaced phases. - View Dependent Claims (12, 13)
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Specification