Invention Grant
- Patent Title: Clock and data recovery circuit having tunable fractional-N phase locked loop
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Application No.: US15959104Application Date: 2018-04-20
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Publication No.: US10224937B1Publication Date: 2019-03-05
- Inventor: Zhaoyin D. Wu , Geoffrey Zhang , Parag Upadhyaya , Kun-Yung Chang
- Applicant: Xilinx, Inc.
- Applicant Address: US CA San Jose
- Assignee: XILINX, INC.
- Current Assignee: XILINX, INC.
- Current Assignee Address: US CA San Jose
- Agent Robert M. Brush
- Main IPC: H03L7/08
- IPC: H03L7/08 ; H04L7/00 ; H04L1/00 ; H03L7/197 ; H03L7/099 ; H04L7/033

Abstract:
An example clock and data recovery (CDR) circuit includes a phase interpolator, a fractional-N phase locked loop (PLL) configured to supply a clock signal to the phase interpolator, and a phase detector configured to generate a phase detect result signal in response to phase detection of data samples and crossing samples of a received signal, the data samples and the crossing samples being generated based on a data phase and a crossing phase, respectively, or a sampling clock supplied by a phase interpolator. The CDR circuit further includes a digital loop filter configured to generate a phase interpolator code for controlling the phase interpolator, the digital loop filter including a phase path and a frequency path. The CDR circuit further includes a control circuit configured to control the digital loop filter to disconnect the frequency path from the phase path and to connect the frequency path to a control input of the fractional-N PLL.
Information query