Dual-Path Resonator Clock Compensation for Phase Noise and Power

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Solution Overview

Problem

Conventional temperature compensation approaches in high-precision timing circuits are inadequate as they lead to increased phase noise and power consumption due to rising bit depths required for frequency stability, especially in addressing higher-order temperature-dependent frequency drifts.

Innovation Solution

A dual-path temperature compensation method using a low-noise analog path for low-order temperature-dependent frequency drift and a nonlinear digital path for higher-order drift, reducing the dynamic range required in the digital path and lowering phase noise and power consumption without compromising frequency stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional digital temperature compensation techniques are used to address higher-order temperature-dependent frequency drift, then frequency stability is improved, but phase noise and power consumption increase due to increased bit depths

Engineering Contradiction:

Improvefrequency stabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The temperature compensation function is segmented into two distinct paths: an analog path handling low-order temperature-dependent frequency drift and a digital path handling higher-order drift. This segmentation allows each path to operate with optimized precision requirements, reducing the bit depth needed in the digital path and thereby lowering power consumption while maintaining overall frequency stability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An analog compensation signal serves as an intermediary that pre-compensates for low-order temperature effects before the signal enters the digital compensation path. This intermediary analog processing reduces the dynamic range and precision requirements of the subsequent digital path, enabling lower bit-depth operation with reduced power consumption

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

Engineering Contradiction:

Improvefrequency stabilityVSAvoidphase noise

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

By segmenting the compensation function into analog and digital paths, the system avoids using high-bit-depth digital compensation for low-order temperature effects. The analog path handles these effects with inherently lower noise, while the digital path only processes higher-order drift with reduced precision requirements, minimizing digital quantization noise and phase noise overall

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The analog compensation signal acts as a noise-reducing intermediary that removes low-order temperature variations before digital processing. This prevents these variations from being amplified by high-bit-depth digital converters, thereby reducing the phase noise contribution from the digital path

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If a single digital compensation path is used for all temperature-dependent frequency drift, then implementation simplicity is maintained, but precision and stability are insufficient for higher-order drift

Engineering Contradiction:

Improvecompensation path structureVSAvoidfrequency stability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The compensation system is divided into specialized segments: an analog path optimized for low-order temperature drift and a digital path optimized for higher-order drift. This segmentation provides the precision needed for each type of drift without requiring an overly complex single-path solution, achieving high stability through functional specialization

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each compensation path is designed with local quality optimized for its specific function: the analog path uses continuous signal processing suitable for low-order drift, while the digital path uses discrete processing optimized for higher-order drift. This localized optimization enables high precision for each segment without requiring maximum precision throughout the entire system

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11228302B1Clock generator with dual-path temperature compensation

Publication Date: 2022.01.18 SITIME CORP

AI summary

In a timing signal generator having a resonator, one or more temperature-sense circuits generate an analog temperature signal and a digital temperature signal indicative of temperature of the resonator. First and second temperature compensation signal generators to generate, respectively, an analog temperature compensation signal according to the analog temperature signal and a digital temperature compensation signal according to the digital temperature signal. Clock generating circuitry drives the resonator into mechanically resonant motion and generates a temperature-compensated output timing signal based on the mechanically resonant motion, the analog temperature compensation signal and the digital temperature compensation signal.