Marvellworld Trade Ltd.

Marvell International Limited

Marvell World Trade Ltd., St. Michael

Olivier Burg

Cao-Thong Tu

Miguel Kirsch

Haisong Wang

Xiang Gao

A multiplying delay-locked loop circuit includes a delay chain including a plurality of variable delay circuits connected in series and having a delay chain output, and a feedback loop including circuitry for deriving a digital control signal representing magnitude and sign of phase offset in the delay chain output, for controlling delay in ones of the variable delay circuits. The circuitry for deriving a digital control signal includes a sampling time-to-digital converter (STDC) configured to operate on a time delay between inputs to generate the digital control signal. The STDC subtracts a second difference the signals derived from the delay chain output and output of the feedback divider from a first difference between the signals derived from the delay chain output and output of the feedback divider to provide a difference value, and the difference value indicates sign and magnitude of output offset in the delay chain output.

Multiplying delay-locked loop using sampling time-to-digital converter

A digital phase locked loop (DPLL) circuit includes a digital-to-time converter (DTC) configured to generate a delayed reference clock signal by delaying a reference clock signal according to a delay control signal and a time-to-digital converter (TDC) coupled to an output of the DTC. The TDC is configured to sample a value of a transition signal according to the delayed reference clock signal and to generate an output signal indicating a phase difference between the delayed clock signal and an input clock signal. A method of controlling a DPLL includes delaying a reference clock signal according to a delay control signal, sampling a value of a transition signal according to the delayed reference clock signal, generating an output signal indicating a phase difference between the delayed clock signal and an input clock signal, and generating a digitally controlled oscillator (DCO) clock signal according to the output signal.

All-digital phase locked loop (ADPLL) including a digital-to-time converter (DTC) and a sampling time-to-digital converter (TDC)

Embodiments include a method comprising: receiving a reference clock signal; generating, by a digitally controlled oscillator, an output signal, wherein the reference clock signal has a first frequency, and wherein the digitally controlled oscillator is configured to generate the output signal at a second frequency; based on the output signal, generating a first feedback signal, wherein the first feedback signal is representative of a phase of the output signal relative to the reference clock signal; based on the first feedback signal, generating a second feedback signal, wherein generating the second feedback signal comprises, in response to the second frequency being an integer multiple of the first frequency, modifying the first feedback signal to generate the second feedback signal; and based on the second feedback signal, generating a control signal, wherein the output signal is generated by the digitally controlled oscillator based on the control signal.

Method and apparatus for avoiding dead zone effects in digital phase locked loops

An all-digital phase locked loop includes a time to digital converter that determines a fractional portion of a phase count. The time to digital converter has a quantization error that may be caused by phase noise, delay errors or skew errors. Several methods and devices may reduce the quantization error. A noise source may add dithering to the reference clock at an input of the time to digital converter. A digital processor may use two successive rising edges of the oscillator signal to count time delays of the time to digital convertor to the reference clock. The digital processor uses these counts to determine a ratio of the time delays and the time period of the oscillator signal for controlling a digitally controlled oscillator. A radio frequency counter circuit detects whether the oscillator signal leads or lags the reference clock because of skew and generates a phase signal to correct the skew.

Methods and devices for implementing all-digital phase locked loop

An all-digital phase locked loop includes a time to digital converter that determines a fractional portion of a phase count. The time to digital converter has a quantization error that may be caused by phase noise, delay errors or skew errors. Several methods and devices may reduce the quantization error. A noise source may add dithering to the reference clock at an input of the time to digital converter. A digital processor may use two successive rising edges of the oscillator signal to count time delays of the time to digital convertor to the reference clock, and uses these counts to determine a ratio of the time delays and the time period of the oscillator signal for controlling a digitally controlled oscillator. A radio frequency counter circuit detects whether the oscillator signal leads or lags the reference clock because of skew and generates a phase signal to correct the skew.

Methods and devices provide for determining whether to operate a radio frequency synthesizer in a first mode of operation or a second mode of operation based on a reference frequency signal. The radio frequency synthesizer includes a digitally-controlled oscillator configured to generate an oscillator signal having an output frequency. A digital frequency locked-loop is configured to control the output frequency of the oscillator signal in a first mode of operation based on a first control signal. A digital phase locked-loop is configured to control the output frequency of the oscillator signal in a second mode of operation based on a second control signal. A controller determines whether to operate in the first mode or second mode based on a reference frequency signal. The controller generates the first or second control signal based on the determination of operating in the first or second mode, respectively.

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Lausanne, Switzerland

Olivier Burg