Clock and data recovery circuits
First Claim
1. A clock and data recovery circuit receiving an input signal and outputting an output signal in phase with the input signal, comprising:
- a phase detection circuit estimating a significant transition of the input signal and outputting a first detection signal;
a first oscillator receiving the first detection signal and outputting a first clock, wherein the first oscillator operates in a first mode during a first period and sequentially in second and synchronization modes during a second period;
a second oscillator receiving the first detection signal and outputting a second clock, wherein the second oscillator operates sequentially in the second and synchronization modes during the first period and operates in the first mode during the second period; and
a flip-flop receiving the input signal and outputting the output signal according to the first and second clocks respectively during the first and second periods,wherein the first oscillator comprises;
a first multiplexer receiving the first clock and the first detection signal and controlled by a first select signal;
a first delay unit coupled to an output terminal of the first multiplexer;
a second multiplexer receiving the second clock and a signal output from the first delay unit and controlled by a second select signal; and
a second delay unit coupled to an output terminal of the second multiplexer and outputting the first clock,wherein when the first oscillator operates in the first mode, the first multiplexer transmits the first clock to the first delay unit according to the first select signal at a first level or transmits the first detection signal to the first delay unit according to the first select signal at a second level; and
wherein when the first oscillator operates in the first mode, the second multiplexer transmits the signal output from the first delay unit to the second delay according to the second select signal.
1 Assignment
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Accused Products
Abstract
A clock and data recovery circuit comprising a phase detection circuit, first and second oscillators, and a flip-flop. The phase detection circuit outputs a detection signal according to a significant transition of an input signal. Each oscillator receives the detection signal and operates alternately in a clock and data recovery mode and a phase-locked mode. When the first oscillator operates in the clock and data recovery mode and outputs a first clock to control the flip-flop to output an output signal, the second oscillator operates in the phase-locked mode to adjust a frequency of a second clock. Before switching to the clock and data recovery mode, the second oscillator synchronizes the second clock with the first clock.
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Citations
24 Claims
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1. A clock and data recovery circuit receiving an input signal and outputting an output signal in phase with the input signal, comprising:
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a phase detection circuit estimating a significant transition of the input signal and outputting a first detection signal; a first oscillator receiving the first detection signal and outputting a first clock, wherein the first oscillator operates in a first mode during a first period and sequentially in second and synchronization modes during a second period; a second oscillator receiving the first detection signal and outputting a second clock, wherein the second oscillator operates sequentially in the second and synchronization modes during the first period and operates in the first mode during the second period; and a flip-flop receiving the input signal and outputting the output signal according to the first and second clocks respectively during the first and second periods, wherein the first oscillator comprises; a first multiplexer receiving the first clock and the first detection signal and controlled by a first select signal; a first delay unit coupled to an output terminal of the first multiplexer; a second multiplexer receiving the second clock and a signal output from the first delay unit and controlled by a second select signal; and a second delay unit coupled to an output terminal of the second multiplexer and outputting the first clock, wherein when the first oscillator operates in the first mode, the first multiplexer transmits the first clock to the first delay unit according to the first select signal at a first level or transmits the first detection signal to the first delay unit according to the first select signal at a second level; and wherein when the first oscillator operates in the first mode, the second multiplexer transmits the signal output from the first delay unit to the second delay according to the second select signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification