Xilinx, Inc.

Yiqin Chen

Charles Walter Boecker

William C Black

Eric Douglas Groen

Moises Emanuel Robinson

Jinghui Lu

Scott Alan Irwin

Joseph Neil Kryzak

Andrew G Jenkins

Aaron Hoelscher

Bernard L Grung

Scott A Irwin

Joseph N Kryzak

Aaron J Hoelscher

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.

Duty cycle correction of a multi-gigahertz clock signal with crossover point control

A programmable logic device includes a plurality of programmable multi-gigabit transceivers, programmable logic fabric, and a control module. Each of the plurality of programmable multi-gigabit transceivers is individually programmed to a desired transceiving mode of operation in accordance with a plurality of transceiver settings. The programmable logic fabric is operably coupled to the plurality of programmable multi-gigabit transceivers and is configured to process at least a portion of the data being transceived via the multi-gigabit transceivers. The control module is operably coupled to produce the plurality of transceiver settings based on a desired mode of operation for the programmable logic device.

Programmable logic device including programmable multi-gigabit transceivers

A high speed data communication system includes a receiver to recover data and clock signals from communicated data. The receiver circuit has a dual phase lock loop (PLL) circuit. A fine loop of the PLL includes a phase detector providing a differential analog voltage output. Transconductance circuitry converts the differential analog voltage output to a low current analog output. The transconductance circuitry has a variable gain which is controlled by an automatic gain adjust circuit. A coarse loop of the PLL allows for fast frequency acquisition of an internal oscillator.

Phase lock loop and automatic gain control circuitry for clock recovery

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Ames, IA, United States of America

Yiqin Chen