Invention Grant
US07496155B1 Duty cycle correction of a multi-gigahertz clock signal with crossover point control
有权
具有交叉点控制的多吉赫兹时钟信号的占空比校正
- Patent Title: Duty cycle correction of a multi-gigahertz clock signal with crossover point control
- Patent Title (中): 具有交叉点控制的多吉赫兹时钟信号的占空比校正
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Application No.: US11228655Application Date: 2005-09-16
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Publication No.: US07496155B1Publication Date: 2009-02-24
- Inventor: Jinghui Lu , Yiqin Chen
- Applicant: Jinghui Lu , Yiqin Chen
- Applicant Address: US CA San Jose
- Assignee: Xilinx, Inc.
- Current Assignee: Xilinx, Inc.
- Current Assignee Address: US CA San Jose
- Agent James Harrison
- Main IPC: H04L27/00
- IPC: H04L27/00

Abstract:
A clock recovery circuit includes a crossover adjustment circuit operable to adjust a crossover point to adjust a corresponding duty cycle. The adjustment circuit comprises a feedback adjustment combining element which is implemented as summing elements and a crossover point control clock amplifier, an operational amplifier with a resistor in place of a low pass filter at an input of the operational amplifier and feedback driver. The summing element within the feedback adjustment combining element combines input clocks with feedback signals, the crossover point control clock amplifier includes adjustment driver, the two cross coupled PMOS along with the resistor connected between them, reshape input clocks, adjust cross over point and provide output clocks with DCD corrected. A modified Miller capacitor comprising a resistor in series with a capacitor across a drain and gate of a cascode transistor pair is utilized in an output stage to adjust corner frequencies.
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