NFC Receiver Sampling Phase Control for ADC Clipping During Charging

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Solution Overview

Problem

NFC devices face challenges in maintaining the operation point of the receiver within its dynamic range during wireless charging due to loading effects, which conventional mechanisms struggle to address without compromising sensitivity.

Innovation Solution

The implementation of a clipping detector and a sampling phase controller in the NFC device adjusts the sampling phase of the receiver based on detected clipping of the analog-to-digital converter, using predefined rules to keep the receiver within its dynamic range without complex optimizations or significant sensitivity reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional mechanisms are used to maintain the operation point within dynamic range, then sensitivity is preserved, but loading effects during wireless charging cause communication failures

Engineering Contradiction:

Improvecommunication stabilityVSAvoidadaptability to loading effects

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system implements a feedback mechanism where the clipping detector continuously monitors the ADC output for clipping conditions and provides this information to the sampling phase controller, which then adjusts the sampling phase accordingly. This closed-loop feedback enables the system to adapt to loading effects during wireless charging while maintaining communication reliability.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The invention changes the sampling phase parameter dynamically based on detected clipping conditions. By adjusting the sampling phase in response to loading effects, the system maintains the operation point within the dynamic range of the ADC, preventing communication failures during wireless charging operations.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the sampling phase is adjusted frequently to prevent clipping, then communication reliability improves, but system complexity increases

Engineering Contradiction:

Improvecommunication reliabilityVSAvoidcontrol mechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system performs self-adjustment by automatically detecting clipping conditions through the clipping detector and correcting the sampling phase through the sampling phase controller without requiring external intervention or complex optimization algorithms. This self-service approach maintains reliability while keeping the control mechanism relatively simple.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The feedback loop between the clipping detector and sampling phase controller provides automatic correction with minimal complexity. The system monitors its own operation and makes necessary adjustments autonomously, avoiding the need for complex external control mechanisms.

Inventive Principle:

Principle #23Feedback

3Reliability

If complex optimizations are applied to maintain dynamic range, then communication stability improves, but sensitivity is reduced

Engineering Contradiction:

Improvecommunication stabilityVSAvoidreceiver sensitivity

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

Instead of applying complex optimizations that would reduce sensitivity, the system uses a simple parameter change (sampling phase adjustment) to maintain dynamic range. This approach preserves receiver sensitivity while achieving communication stability by keeping the operation point within the valid range.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention extracts and addresses only the specific issue of sampling phase misalignment caused by loading effects, rather than applying comprehensive complex optimizations. By focusing on this single critical parameter, the system maintains sensitivity while achieving sufficient communication stability.

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 ensures stable communication by maintaining the receiver's operation point within its dynamic range, preventing communication failures while preserving sensitivity.

Implementation Method 1

a receiver, the receiver comprising an analog-to-digital converter

Methodology Applied

Scientific EffectAnalog-to-digital conversion:

Implementation Method 2

a clipping detector configured to detect clipping of one or more signals processed by the analog-to-digital converter

Methodology Applied

Scientific EffectSignal clipping detection:

Implementation Method 3

a sampling phase controller operatively coupled to the clipping detector, wherein the sampling phase controller is configured to adjust a sampling phase of the receiver based on an output of the clipping detector

Methodology Applied

Scientific EffectSampling phase adjustment:

Data Source

PatentUS20250392318A1Near field communication device and operating method

Publication Date: 2025.12.25 NXP BV

AI summary

In accordance with a first aspect of the present disclosure, a near field communication (NFC) device is provided, comprising: a receiver, said receiver including an analog-to-digital converter; a clipping detector configured to detect clipping of one or more signals processed by the analog-to-digital converter; and a sampling phase controller operatively coupled to the clipping detector, wherein said sampling phase controller is configured to adjust a sampling phase of the receiver based on an output of the clipping detector. In accordance with a second aspect of the present disclosure, a method of operating a near field communication (NFC) device is conceived.