Quadrature-based injection locking of ring oscillators
AssigneeCalifornia Institute of Technology
InventorsMayank Raj, Azita Emami
Life of this patent
Estimating the term…
Abstract
Technologies are generally described for quadrature-based injection-locking offing oscillators. In some examples, an external signal may be injected into a ring oscillator. Phase signals may be measured from within the ring oscillator and used to determine a mean quadrature error (MQE) that characterizes the difference in frequency between the external signal and the ring oscillator's natural frequency. A control signal may then be generated from the MQE and used to adjust the ring oscillator natural frequency to reduce the difference between the ring oscillator natural frequency and the external signal.
Claims20
An injection-locked ring oscillator system, comprising:
- a plurality of inverters configured to receive an external signal with an injection frequency;
- a phase detector module coupled to the plurality of inverters, wherein the phase detector module is configured to:
- detect a first phase signal, formed from a coupling of a natural frequency of the injection-locked ring oscillator system and the injection frequency, from a first inverter of the plurality of inverters;
- detect a second phase signal, formed from the coupling of the natural frequency and the injection frequency, from a second inverter of the plurality of inverters;
- detect a mismatch between the injection frequency and the natural frequency;
- and
- identify phase errors in the first phase signal and the second phase signal based on the mismatch;
- and
- a control module coupled to the phase detector module, wherein the control module is configured to:
- generate a control signal based on the phase errors, wherein the control signal is configured to control the injection-locked ring oscillator system.
A clock signal distribution circuit, comprising:
- a clock signal injection stage, wherein the clock signal injection stage is configured to:
- receive a clock signal;
- and
- use the clock signal to output an injection signal with an injection frequency;
- a ring oscillator with a natural frequency and coupled to the clock signal injection stage, wherein the ring oscillator configured to:
- receive the injection signal and oscillation signals;
- and
- a quadrature phase detector module coupled to the ring oscillator, wherein the quadrature phase detector module is configured to:
- detect, from the ring oscillator, phase signals formed from a coupling of the natural frequency and the injection frequency;
- and
- determine a mean quadrature error (MQE) from the phase signals, wherein the MQE is usable to generate a control signal to control the ring oscillator.
A method to injection-lock a ring oscillator that includes a plurality of inverters and a natural frequency, the method comprising:
- injecting an external signal with an injection frequency into at least one of the plurality of inverters;
- detecting a first phase signal, formed from a coupling of the natural frequency and the injection frequency, from a first inverter in the plurality of inverters;
- detecting a second phase signal, formed from the coupling of the natural frequency and the injection frequency, from a second inverter in the plurality of inverters;
- detecting a mismatch between the injection frequency and the natural frequency;
- identifying phase errors in the first phase signal and the second phase signal based on the mismatch:
- and
- generating a control signal based on the phase errors, wherein the control signal is configured to control the ring oscillator.
Dependencies are inferred from the claim text.