SPAD Array Active Quenching Circuit Power Control

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Solution Overview

Problem

Conventional multi-pixel SiPMs face challenges in achieving high resolution and dynamic range while managing power consumption, especially in varying environmental conditions, and require multifunctionality to complement other sensors in LiDAR systems.

Innovation Solution

A photodetector configuration with a plurality of channels, each comprising SPAD units with active quenching circuits and control circuits that selectively enable or disable output, reducing power consumption by preventing Geiger current flow in non-outputting channels and using integrators to expand dynamic range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If active quenching technique is used to speed up recovery after light detection, then detection speed is improved, but power consumption increases due to large current flow

Engineering Contradiction:
Improverecovery speedVSAvoidpower consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic control of the active quenching circuit by introducing a control signal that selectively activates or deactivates the quenching function based on operational requirements. When high-speed recovery is needed, the quenching circuit is activated; when power consumption needs reduction, the circuit is deactivated, allowing the system to adapt its power consumption and recovery speed characteristics dynamically

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies the active quenching technique selectively to specific channels or regions rather than uniformly across all channels. By controlling which channels receive active quenching, the system optimizes the balance between recovery speed and power consumption for different parts of the sensor array based on local requirements

Inventive Principle:
Principle #3Local quality

2Use of energy by moving object

If current is restricted to reduce power consumption, then power consumption is reduced, but recovery is delayed causing measurement defects

Engineering Contradiction:
Improvepower consumptionVSAvoidmeasurement reliability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The control circuit dynamically adjusts the quenching current level based on operational conditions. When measurement reliability is critical, higher current is supplied to ensure fast recovery; when power consumption is the priority, current is reduced while maintaining adequate recovery performance through intelligent control timing

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If multi-pixel SiPM array is used to achieve high resolution, then resolution is improved, but sensor area is restricted limiting dynamic range

Engineering Contradiction:
ImproveresolutionVSAvoidsensor area
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent divides the sensor into multiple independent channels, each with its own SPAD array and active quenching circuit. This segmentation allows different channels to operate independently with optimized parameters, enabling high resolution within each channel while the combined system provides extended dynamic range through multi-channel operation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a two-dimensional spatial arrangement to a multi-dimensional operational space by adding the time dimension through sequential channel activation and the functional dimension through multiple operating modes. This allows the system to achieve high resolution in space while expanding dynamic range through temporal and functional multiplexing

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Measurement precision

If conventional multi-pixel SiPM is used, then high sensitivity is achieved, but it cannot operate reliably in various environmental conditions

Engineering Contradiction:
ImprovesensitivityVSAvoidenvironmental adaptability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic adaptation to environmental conditions through the control circuit that adjusts operating parameters based on detected conditions. The system can switch between different operational modes (single-photon detection, analog mode, integration mode) and adjust quenching current levels to maintain optimal performance across varying temperature, light level, and humidity conditions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent designs the photodetector system with multiple functional modes including single-photon detection mode, analog detection mode, and integration mode. This multi-functionality allows the same hardware to adapt to different environmental conditions and application requirements, making the system universally applicable across diverse operating environments

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 configuration enhances the LiDAR system's ability to achieve high resolution and dynamic range while reducing power consumption, ensuring reliable operation in diverse environments and supporting multifunctional capabilities.

Implementation Method 1

a first avalanche photodiode (SiAPD) 42 having a cathode connected to the other end of the resistor 41

Methodology Applied
Scientific EffectAvalanche breakdown: Avalanche Breakdown

Implementation Method 2

an active quenching circuit which performs active quenching of the avalanche photodiode

Methodology Applied
Scientific EffectActive quenching:

Data Source

PatentEP3796035B1SPAD photodetector array with active quenching and output control
Publication Date: 2024.09.04 KK TOSHIBA
  • EP3796035B1 patent drawingFigure 1
  • EP3796035B1 patent drawingFigure 2~3
  • EP3796035B1 patent drawingFigure 4~5(B)

AI summary

A photodetector (14) includes a plurality of channels (21) each having a plurality of SPAD units (32), each SPAD unit having an avalanche photodiode (42). The photodetector (14) is capable of selecting outputting or non-outputting of the channels (21). The SPAD unit (32) includes: an active quenching circuit (43, 44) which performs active quenching of the avalanche photodiode (42); and a control circuit(11) which brings the active quenching circuit (43, 44) which corresponds to the channel where non-outputting is selected into an operable state.