Injection-Locked Clock Supply for Low-Power Frequency Accuracy

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Solution Overview

Problem

In low-power wireless communications, frequency synthesizers such as PLLs or VCOs consume a majority of the power used by wireless transmission chips, posing a challenge for devices with limited battery size and charge, like wireless sensor nodes and telemetry systems.

Innovation Solution

A clock frequency supply device comprising a frequency tuner, injector, and oscillator that tunes the oscillation frequency based on an input carrier frequency, generates a reference clock signal, and deactivates the frequency tuner after tuning is complete to reduce power consumption, using a gate to restrict carrier frequency supply and an injector to enable signal injection only after tuning is finished.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the frequency tuner remains active to maintain frequency accuracy, then the reference clock frequency remains locked to the carrier frequency, but power consumption increases

Engineering Contradiction:

Improvereference clock frequency accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The frequency tuner performs frequency calibration in advance before the main operation begins. The calibration phase tunes the oscillator to the correct frequency based on the carrier signal, and once calibrated, the tuner can be deactivated while the oscillator maintains its frequency through free-running mode, thus achieving frequency accuracy without continuous power consumption from the tuner

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system operates in periodic cycles between active calibration mode and free-running mode. During periodic calibration intervals, the frequency tuner is activated to correct any drift, while between these intervals, the system operates in low-power free-running mode, creating a periodic pattern of high-accuracy and low-power states

Inventive Principle:

Principle #19Periodic action

2Use of energy by moving object

If the frequency tuner is deactivated to reduce power consumption, then power usage decreases, but frequency calibration time increases

Engineering Contradiction:

Improvepower consumptionVSAvoidcalibration time

Core Design Contradiction:

Use of energy by moving objectVSLoss of time

Solution Approach 1:

The frequency tuner performs comprehensive frequency calibration in advance before the main operation begins. The calibration phase tunes the oscillator to the correct frequency based on the carrier signal, and once calibrated, the tuner can be deactivated while the oscillator maintains its frequency through free-running mode, thus achieving frequency accuracy without continuous power consumption from the tuner

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If the frequency tuner operates continuously to maintain frequency lock, then frequency accuracy is improved, but device complexity increases

Engineering Contradiction:

Improvefrequency lock accuracyVSAvoidcontrol circuit complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The frequency tuning function is extracted as a separate, independent calibration phase rather than being integrated into continuous operation. The tuner is used only during the initial calibration stage and then removed from the active circuit, simplifying the overall control logic by eliminating the need for continuous tuning control mechanisms

Inventive Principle:

Principle #2Taking out (Extraction)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach reduces overall power consumption in low-power wireless communications by minimizing the power used by the frequency tuner and maintaining the oscillation frequency locked to the carrier frequency, thereby generating an accurate clock frequency with lower power usage and reduced calibration time.

Implementation Method 1

an oscillator configured to generate a reference clock signal with a reference clock frequency based on the injected input signal

Methodology Applied

Scientific EffectOscillation: Harmonic Oscillator

Implementation Method 2

a frequency tuner configured to receive an input signal with a carrier frequency, and tune an oscillation frequency of an oscillator based on the carrier frequency

Methodology Applied

Scientific EffectFrequency tuning:

Implementation Method 3

an injector configured to inject the input signal directly into the oscillator after the tuning of the oscillation frequency is completed

Methodology Applied

Scientific EffectInjection locking:

Data Source

PatentUS10903842B2Device and method with clock frequency supply

Publication Date: 2021.01.26 SAMSUNG ELECTRONICS CO LTD

AI summary

A clock frequency supply device includes: a frequency tuner configured to receive an input signal with a carrier frequency, and tune an oscillation frequency of an oscillator based on the carrier frequency; an injector configured to inject the input signal directly into the oscillator after the tuning of the oscillation frequency is completed; and an oscillator configured to generate a reference clock signal with a reference clock frequency based on the injected input signal.