Adaptive Driving Beam Power Supply Control for Pixel Voltage Stability

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Solution Overview

Problem

The existing Adaptive Driving Beam (ADB) lamp systems face challenges in efficiently supplying power to array-type light-emitting devices, leading to increased power consumption and potential flickering or lighting issues due to voltage drops and varying minimum operating voltages across pixels.

Innovation Solution

A lamp system that includes an array-type light-emitting device with multiple pixel circuits coupled in parallel and a power supply circuit with a DC/DC converter and a power supply control circuit. The control circuit dynamically sets a target value for the output voltage based on the light distribution pattern and voltage drops, ensuring stable power supply and reducing unnecessary consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed high target voltage is set for the power supply circuit, then all pixel circuits can operate (avoiding flickering), but power consumption increases unnecessarily when not all pixels are active

Engineering Contradiction:
Improveoperational stabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies dynamics by making the target voltage adjustable rather than fixed. The power supply control circuit dynamically changes the target voltage based on the number of active pixel circuits. When fewer pixels are active, the target voltage is reduced accordingly, avoiding unnecessary power consumption while maintaining sufficient voltage for operational pixels to prevent flickering.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the voltage parameter adaptively. Instead of maintaining a constant high target voltage, the system modifies the target voltage level according to the actual number of active pixel circuits. This parameter change allows the system to optimize power consumption while ensuring reliable operation of the active pixels.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If the target voltage is reduced to save power, then power consumption decreases, but voltage drops may cause flickering or lighting issues in pixel circuits

Engineering Contradiction:
Improvepower consumptionVSAvoidoperational stability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent implements feedback control where the power supply control circuit monitors the number of active pixel circuits and adjusts the target voltage accordingly. This feedback mechanism ensures that the target voltage is reduced only to the extent necessary for power savings while maintaining the minimum required voltage for active pixels, thus preventing flickering and operational instability.

Inventive Principle:
Principle #23Feedback

3Illumination intensity

If more pixel circuits are activated to improve light distribution, then illumination coverage increases, but power consumption and voltage drops increase

Engineering Contradiction:
Improvelight distributionVSAvoidpower consumption
Core Design Contradiction:
Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts the target voltage based on the number of active pixel circuits. When more pixels are activated to improve light distribution, the target voltage is increased accordingly to ensure sufficient power delivery. This dynamic adjustment allows the system to provide adequate illumination while minimizing power consumption by not over-provisioning voltage when fewer pixels are active.

Inventive Principle:
Principle #15Dynamics

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 enables stable power supply to the array-type light-emitting device, reduces power consumption, and prevents flickering or lighting issues by accurately managing the power supply voltage based on the light distribution pattern and voltage drops.

Implementation Method 1

a DC/DC converter 224 and a power supply control circuit 225

Methodology Applied
Scientific EffectDC/DC conversion:

Implementation Method 2

each include a light-emitting element 213 and a current source 214 coupled in series

Methodology Applied
Scientific EffectLight emission: Light Emitting Diode

Data Source

PatentEP4164339B1Vehicular lamp system, power supply circuit
Publication Date: 2025.02.19 KOITO MFG CO LTD
  • EP4164339B1 patent drawingFigure 1
  • EP4164339B1 patent drawingFigure 2
  • EP4164339B1 patent drawingFigure 3A~3B

AI summary

An array-type light-emitting device 212 includes multiple pixel circuits PIX electrically coupled in parallel and spatially arranged in a matrix. A power supply circuit 220 supplies electric power to the array-type light-emitting device 212. A DC/DC converter 224 has an output coupled to a power supply terminal of the array-type light-emitting device 212 via a power supply line. A power supply control circuit 225 sets a target value VCNT(REF) that corresponds to a light distribution pattern, and controls the DC/DC converter 224 such that the control target voltage VCNT approaches the target value VCNT(REF).