High performance phase locked loop
AssigneeKandou Labs, S.A.
InventorArmin Tajalli
Life of this patent
Estimating the term…
Abstract
Methods and systems are described for receiving N phases of a local clock signal and M phases of a reference signal, wherein M is an integer greater than or equal to 1 and N is an integer greater than or equal to 2, generating a plurality of partial phase error signals, each partial phase error signal formed at least in part by comparing (i) a respective phase of the M phases of the reference signal to (ii) a respective phase of the N phases of the local clock signal, and generating a composite phase error signal by summing the plurality of partial phase error signals, and responsively adjusting a fixed phase of a local oscillator using the composite phase error signal.
Claims20
A method comprising:
- obtaining a plurality of phases of a reference signal and a plurality of phases of a local oscillator signal;
- forming at least two partial phase-error signals, each partial phase-error signal formed by:
- generating a variable-duty-cycle waveform based on an exclusive OR (XOR) phase comparison between a phase of the reference signal and a phase of the local oscillator signal, wherein a duty cycle of the variable-duty cycle waveform is indicative of a phase error between the phase of the reference signal and the phase of the local oscillator signal;
- and
- providing the variable-duty-cycle waveform to a respective charge pump as a charge pump control signal to generate the partial phase-error signal;
- performing a summation of the plurality of partial phase-error signals by injecting or removing charge from a capacitive element according to the plurality of partial phase-error signals to generate a composite phase-error signal;
- and
- providing the composite phase-error signal to a local oscillator generating the plurality of phases of the local oscillator signal.
An apparatus comprising:
- a multi-phase comparator configured to obtain a plurality of phases of a reference signal and a plurality of phases of a local oscillator signal, the multi-phase comparator comprising:
- a plurality of partial phase comparators configured to form at least two partial phase-error signals, each partial phase-error signal formed by generating a variable-duty-cycle waveform based on an exclusive OR phase comparison between a phase of the reference signal and a phase of the local oscillator signal, wherein a duty cycle of the variable-duty cycle waveform is indicative of a phase error between the phase of the reference signal and the phase of the local oscillator signal;
- and
- a plurality of charge pumps configured to receive respective variable-duty-cycle waveforms as a charge pump control signal and to responsively generate the partial phase-error signal;
- and
- a capacitive element configured to generate a composite phase-error signal based on charge injected or removed from the capacitive element according to the plurality of partial phase-error signals;
- and
- a local oscillator configured to receive the composite phase-error signal and to responsively adjust a fixed phase of the local oscillator according to the composite phase-error signal, the local oscillator generating the plurality of phases of the local oscillator signal.
Dependencies are inferred from the claim text.