PLL Lock Detection Circuit for RF Communication Stability

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Solution Overview

Problem

Existing electronic devices face challenges in accurately determining the normal or abnormal operation of Phase Locked Loop (PLL) circuits, leading to potential component damage and network disconnection due to incorrect frequency band locking and impedance distortion issues.

Innovation Solution

An electronic device is designed with a duplexer containing band pass filters and a transceiver that includes multiple PLL circuits and mixers to detect and convert RF signals, along with filters to attenuate specific frequency bands, generating a status signal indicating whether the PLL circuit's frequency band is locked to a designated reference frequency band, thereby preventing component damage and network disconnection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the FBRX method is used to determine PLL circuit operation status, then the determination process is simple, but incorrect operation determinations occur due to errors in band pass characteristics of the duplexer and impedance distortion of the antenna

Engineering Contradiction:

Improvedetermination process simplicityVSAvoidoperation status determination accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent introduces a dedicated detection circuit as an intermediary component between the mixer and power amplifier circuit. This detection circuit specifically monitors the RF signal to determine PLL operation status, separating the detection function from the main signal path and avoiding interference from duplexer band pass characteristics and antenna impedance distortion that affect the FBRX method.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If the FBRX acquires power after the duplexer, then the measurement path is simple, but the acquired power is affected by errors in band pass characteristics of the duplexer

Engineering Contradiction:

Improvemeasurement path complexityVSAvoidpower measurement accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The detection circuit performs preliminary detection of the RF signal before it passes through the duplexer. By detecting the signal at an earlier stage in the signal path (between the mixer and power amplifier circuit), the system obtains accurate PLL operation status information before the signal is affected by duplexer band pass characteristics or antenna impedance distortion.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If the PLL circuit is used for converting RF signal to baseband signal in FBRX, then the existing circuit resources are utilized, but errors occur in determining normal or abnormal operation

Engineering Contradiction:

Improvecircuit resource utilizationVSAvoidoperation status determination accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent segments the detection function from the main signal conversion function. A dedicated detection circuit is created specifically for monitoring PLL operation status, while the main mixer and baseband conversion circuits continue their primary functions. This separation ensures that the detection process does not interfere with or get interfered by the signal conversion process, eliminating the errors that occur when using the same circuit for both purposes.

Inventive Principle:

Principle #1Segmentation

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

The solution effectively determines the normal operation of PLL circuits, preventing component damage and network disconnection by accurately assessing frequency band locking, thus ensuring reliable communication services.

Implementation Method 1

a first band pass filter (BPF) configured to output a first radio frequency (RF) signal of a transmission frequency band and a second BPF configured to output a second RF signal of a reception frequency band

Methodology Applied

Scientific EffectBand pass filtering: Filter (electronic)

Implementation Method 2

a first mixer configured to convert a first baseband signal received from the processor into the first RF signal by using the first reference signal, and a second mixer configured to convert the second RF signal received from the second BPF into a second baseband signal

Methodology Applied

Scientific EffectMixing: Heterodyne

Implementation Method 3

a first filter configured to attenuate power of a frequency band higher than the second baseband and a second filter configured to attenuate power of a frequency band lower than the third baseband

Methodology Applied

Scientific EffectFrequency selective attenuation: Filter (electronic)

Data Source

PatentUS11271573B2Electronic device including phase locked loop circuit used for radio frequency communication

Publication Date: 2022.03.08 SAMSUNG ELECTRONICS CO LTD

AI summary

Disclosed is an electronic device that is configured to determine whether a phase locked loop (PLL) circuit is operating normally, thereby preventing component damage in the electronic device and preventing disconnection from a communication network.