DIGITALLY ASSISTED FEEDBACK LOOP FOR DUTY-CYCLE CORRECTION IN AN INJECTION-LOCKED PLL
First Claim
1. A duty-cycle correction circuit for an injection-locked phase-locked loop (PLL), comprising a digital calibration circuit, which performs a duty-cycle correction operation by:
- obtaining a pattern of positive and negative error pulses at rising and falling edges of a reference clock signal for the injection-locked PLL, wherein the pattern specifies deviations of the reference clock signal from a 50% duty cycle;
multiplying the pattern of positive and negative error pulses by a duty-cycle distortion (DCD) template, which specifies a sign of a duty-cycle error for the reference clock signal, to calculate duty-cycle distortion values;
accumulating the duty-cycle distortion values to produce a duty-cycle-error amplitude;
multiplying the duty-cycle-error amplitude by the DCD template to produce a duty-cycle correction signal; and
using the duty-cycle correction signal to compensate for timing errors in the injection-locked PLL, which are caused by duty-cycle variations in the reference clock signal.
1 Assignment
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Accused Products
Abstract
We disclose a system, which performs a duty-cycle correction operation for an injection-locked phase-locked loop (PLL). The system first obtains a pattern of positive and negative error pulses at rising and falling edges of a reference clock signal for the injection-locked PLL, wherein the pattern specifies deviations of the reference clock signal from a 50% duty cycle. The system multiplies the pattern of positive and negative error pulses by a duty-cycle distortion (DCD) template, which specifies a sign of a duty-cycle error for the reference clock signal, to calculate duty-cycle distortion values. The system then accumulates the duty-cycle distortion values to produce a duty-cycle-error amplitude. Next, the system multiplies the duty-cycle-error amplitude by the DCD template to produce a duty-cycle correction signal. Finally, the system uses the duty-cycle correction signal to compensate for timing errors in the injection-locked PLL, which are caused by duty-cycle variations in the reference clock signal.
3 Citations
20 Claims
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1. A duty-cycle correction circuit for an injection-locked phase-locked loop (PLL), comprising a digital calibration circuit, which performs a duty-cycle correction operation by:
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obtaining a pattern of positive and negative error pulses at rising and falling edges of a reference clock signal for the injection-locked PLL, wherein the pattern specifies deviations of the reference clock signal from a 50% duty cycle; multiplying the pattern of positive and negative error pulses by a duty-cycle distortion (DCD) template, which specifies a sign of a duty-cycle error for the reference clock signal, to calculate duty-cycle distortion values; accumulating the duty-cycle distortion values to produce a duty-cycle-error amplitude; multiplying the duty-cycle-error amplitude by the DCD template to produce a duty-cycle correction signal; and using the duty-cycle correction signal to compensate for timing errors in the injection-locked PLL, which are caused by duty-cycle variations in the reference clock signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of performing a duty-cycle correction operation for an injection-locked phase-locked loop (PLL), comprising:
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obtaining a pattern of positive and negative error pulses at rising and falling edges of a reference clock signal for the injection-locked PLL, wherein the pattern specifies deviations of the reference clock signal from a 50% duty cycle; multiplying the pattern of positive and negative error pulses by a duty-cycle distortion (DCD) template, which specifies a sign of a duty-cycle error for the reference clock signal, to calculate duty-cycle distortion values; accumulating the duty-cycle distortion values to produce a duty-cycle-error amplitude; multiplying the duty-cycle-error amplitude by the DCD template to produce a duty-cycle correction signal; and using the duty-cycle correction signal to compensate for timing errors in the injection-locked PLL, which are caused by duty-cycle variations in the reference clock signal. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A computer system, comprising:
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at least one processor and at least one associated memory; and a clock generator that provides a clock signal for the at least one processor, wherein the clock generator is implemented using an injection-locked phase-locked loop (PLL), and includes a duty-cycle correction; wherein the duty-cycle correction comprises a digital circuit, which performs a duty-cycle correction operation by; obtaining a pattern of positive and negative error pulses at rising and falling edges of a reference clock signal for the injection-locked PLL, wherein the pattern specifies deviations of the reference clock signal from a 50% duty cycle, multiplying the pattern of positive and negative error pulses by a duty-cycle distortion (DCD) template, which specifies a sign of a duty-cycle error for the reference clock signal, to calculate duty-cycle distortion values; accumulating the duty-cycle distortion values to produce a duty-cycle-error amplitude, multiplying the duty-cycle-error amplitude by the DCD template to produce a duty-cycle correction signal, and using the duty-cycle correction signal to compensate for timing errors in the injection-locked PLL, which are caused by duty-cycle variations in the reference clock signal. - View Dependent Claims (20)
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Specification