Clock Synchronization Circuit With Switchable Reference Paths

Solution Overview

Problem

Conventional communication devices require at least two clock generator devices for internal and external reference clock synchronization, occupying a large area on the printed circuit board and increasing costs.

Innovation Solution

A clock synchronization circuit with an external reference signal processing module, phase detector, voltage control conversion module, and clock generator, utilizing a switch module to selectively connect either a digital-to-analog converter or loop filtering module with the clock generator, allowing for synchronization of internal or external reference clocks with fewer devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If at least two clock generator devices are used for internal and external reference clock synchronization, then the synchronization function is achieved, but the printed circuit board area occupied increases and costs increase

Engineering Contradiction:

Improveclock synchronization capabilityVSAvoidprinted circuit board area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The single clock generator device is designed to perform multiple functions: it can generate both internal reference clocks and external reference clocks, and can switch between different clock sources (internal oscillator, external crystal oscillator, external reference clock input) through the control module. This multi-functionality eliminates the need for separate clock generator devices for internal and external synchronization, reducing PCB area while maintaining full synchronization capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines multiple clock generation and switching functions into a single integrated clock generator device. The control module integrates the switching logic to select between different clock sources (internal oscillator output, external crystal oscillator output, external reference clock input), merging what would traditionally require separate devices into one unified component, thereby reducing the overall PCB area occupied.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If at least two clock generator devices are used for internal and external reference clock synchronization, then the synchronization function is achieved, but the total cost increases

Engineering Contradiction:

Improveclock synchronization capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The single clock generator device is designed to perform multiple functions: it can generate both internal reference clocks and external reference clocks, and can switch between different clock sources (internal oscillator, external crystal oscillator, external reference clock input) through the control module. This multi-functionality eliminates the need for separate clock generator devices for internal and external synchronization, reducing PCB area while maintaining full synchronization capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines multiple clock generation and switching functions into a single integrated clock generator device. The control module integrates the switching logic to select between different clock sources (internal oscillator output, external crystal oscillator output, external reference clock input), merging what would traditionally require separate devices into one unified component, thereby reducing the overall PCB area occupied.

Inventive Principle:

Principle #5Merging (Combining)

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

Reduces the area occupied by the printed circuit board and saves costs by enabling switching between internal and external reference clocks with fewer clock generator devices.

Implementation Method 1

The voltage control conversion module includes a digital-to-analog converter

Methodology Applied

Scientific EffectDigital-to-analog conversion:

Implementation Method 2

a phase detector, a voltage control conversion module

Methodology Applied

Scientific EffectPhase detection:

Implementation Method 3

the loop filtering module and a first switch module

Methodology Applied

Scientific EffectLoop filtering: Filter (electronic)

Data Source

PatentUS12356348B2Clock synchronization circuit, control method, printed circuit board and communication device

Publication Date: 2025.07.08 ZTE CORP

AI summary

Disclosed are a clock synchronization circuit, a control method, a printed circuit board and a communication device. The clock synchronization circuit includes an external reference signal processing module, a phase detector, a voltage control conversion module, a clock generator, and a first frequency divider.