Delay locked loop circuitry for clock delay adjustment
First Claim
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1. A delay locked loop circuit, comprising:
- a first loop circuit including a first adjustable delay section to provide a first clock signal having a controlled phase relationship with respect to an external clock signal; and
a second loop circuit, coupled to the first loop circuit, the second loop circuit comprising;
a first phase detector to receive an input clock signal and a first feedback clock signal, the first phase detector to provide a signal that is representative of a phase difference between the first feedback clock signal and the input clock signal;
a first control circuit coupled to the first phase detector, the first control circuit to provide a plurality of control signals based on the signal that is representative of the phase difference between the first feedback clock signal and the input clock signal; and
a selection block coupled to the first adjustable delay section, the selection block to adjust a phase of a second clock signal based on the plurality of control signals and the first clock signal, wherein the second clock signal is distinct from the first clock signal and is used to generate the first feedback clock signal.
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Abstract
A receiver adapted to be coupled to a data bus and configured to receive data in accordance with a receive clock includes first and second delay-locked loops. The first delay-locked loop is configured to generate a plurality of phase vectors from a first reference clock, and the second delay-locked loop is coupled to the first delay-locked loop and configured to generate the receive clock from at least one phase vector selected from the plurality of phase vectors and a second reference clock.
52 Citations
19 Claims
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1. A delay locked loop circuit, comprising:
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a first loop circuit including a first adjustable delay section to provide a first clock signal having a controlled phase relationship with respect to an external clock signal; and a second loop circuit, coupled to the first loop circuit, the second loop circuit comprising; a first phase detector to receive an input clock signal and a first feedback clock signal, the first phase detector to provide a signal that is representative of a phase difference between the first feedback clock signal and the input clock signal; a first control circuit coupled to the first phase detector, the first control circuit to provide a plurality of control signals based on the signal that is representative of the phase difference between the first feedback clock signal and the input clock signal; and a selection block coupled to the first adjustable delay section, the selection block to adjust a phase of a second clock signal based on the plurality of control signals and the first clock signal, wherein the second clock signal is distinct from the first clock signal and is used to generate the first feedback clock signal. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of operation in a delay locked loop circuit, the method comprising:
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generating a first clock signal in a first loop circuit such that the first clock signal includes a controlled phase relationship with respect to an external clock signal; and in a second loop circuit coupled to the first loop circuit; comparing a phase of an input clock signal to a phase of a feedback clock signal to provide a signal that is representative of a phase difference between the feedback clock signal and the input clock signal; generating a plurality of control signals based on the signal that is representative of the phase difference between the feedback clock signal and the input clock signal; and adjusting a phase of a second clock signal based on the plurality of control signals and the first clock signal, wherein the second clock signal is distinct from the first clock signal and is used to generate the feedback clock signal. - View Dependent Claims (8, 9, 10, 11, 12)
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13. An integrated circuit memory device, comprising:
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a first loop circuit including a first adjustable delay section to provide a first clock signal having a controlled phase relationship with respect to an external clock signal; a second loop circuit including a selection block coupled to the first adjustable delay section, the selection block to adjust a phase of a second clock signal based on the first clock signal and a phase difference between a first feedback clock signal and an input clock signal, wherein the second clock signal is distinct from the first clock signal and is used to generate the first feedback clock signal; and a transmitter circuit to output data on both edges of the second clock signal. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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Specification