LiDAR Differential Comparator Timing for Amplitude Estimation

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Solution Overview

Problem

Time-of-flight systems face challenges in precise amplitude estimation due to the limitations of digitization and thresholding techniques, which are either expensive or imprecise and prone to pulse pileup issues.

Innovation Solution

A differential comparator-based system that includes a signal delay component, differential comparator, and a time-to-digital converter to generate LiDAR data with accurate distance and amplitude estimation by analyzing the rising and falling edges of a digital output signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If digitization (high-speed ADC) is used for waveform detection, then measurement precision is improved, but device complexity and cost increase significantly

Engineering Contradiction:

Improvewaveform detection precisionVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex electronic digitization systems (ADC) with a simpler optical-based differential comparator system. The differential comparator uses optical signal comparison to achieve precise waveform detection without requiring high-speed analog-to-digital conversion, thereby reducing device complexity while maintaining measurement precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a differential comparator as an intermediary device between the optical signal and the final measurement. This comparator acts as a mediator that simplifies the detection process by comparing optical signals directly, avoiding the need for complex digitization while preserving measurement accuracy.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If thresholding is used for waveform detection, then device complexity is reduced, but amplitude estimation precision deteriorates due to pulse pileup issues

Engineering Contradiction:

Improvesystem complexityVSAvoidamplitude estimation precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent inverts the traditional thresholding approach by using a differential comparator that compares the optical signal with a delayed version of itself. Instead of applying a fixed threshold, the system inverts the problem by detecting the difference between the signal at two different times, which eliminates pulse pileup issues and enables precise amplitude estimation while keeping the system simple.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent applies preliminary action by delaying the optical signal before comparison. The delay line creates a time-shifted version of the signal in advance, allowing the differential comparator to detect amplitude information from the difference between the original and delayed signals. This preliminary timing adjustment prevents pulse pileup and enables accurate amplitude measurement.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If thresholding is used for waveform detection, then cost is reduced, but reliability deteriorates due to pulse pileup issues

Engineering Contradiction:

Improvesystem costVSAvoidamplitude estimation reliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces the unreliable thresholding mechanism with a differential comparator-based optical comparison system. This substitution maintains low cost while significantly improving reliability by eliminating pulse pileup issues through the differential comparison approach, which inherently rejects common-mode noise and interference.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 system provides precise amplitude estimation while being cost-effective and insensitive to noise, enabling accurate object detection and autonomous vehicle operations.

Implementation Method 1

The time-of-flight principle is an imaging technique that can be used to resolve the distance between a sensor and an object. Time-of-flight systems typically operate by measuring the time difference between the emission of a signal and its return to the sensor after being reflected by an object.

Methodology Applied

Scientific EffectTime of flight: Time of Flight

Implementation Method 2

a signal delay component configured to: receive, at a delay input, a LiDAR output signal including an analog waveform from a LiDAR system, and provide, at a delay output, a time-delayed LiDAR output signal including a time-delayed analog waveform

Methodology Applied

Scientific EffectSignal delay:

Data Source

PatentUS20260050069A1System and method for differential comparator-based time-of-flight measurement with amplitude estimation

Publication Date: 2026.02.19 LG INNOTEK CO LTD

AI summary

A system including a splitter configured to divide a LiDAR output signal including an analog waveform; a time delay component configured to: receive the LiDAR output signal and generate a time-delayed LiDAR output signal including a time-delayed analog waveform; a differential comparator configured to: receive, at a first comparator input, the LiDAR output signal, receive, at a second comparator input, the time-delayed LiDAR output signal and provide, at a comparator output, a digital output signal; and at least one processor configured to: generate LiDAR data including distance and an amplitude based on a rising edge and a falling edge of the digital output signal, and perform amplitude estimation for detection of a subsequent return LiDAR signal.