Adaptive Voltage Thresholds for Automotive Lighting Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional lighting devices face challenges in detecting abnormal output voltages and preventing failures, particularly due to open circuit failures or bad connections, which can lead to excessive voltage application to the light source, potentially causing damage.

Innovation Solution

A lighting device with a controller that measures output voltage and adjusts the operation of a power converter and bypass switch to prevent excessive voltage application, using threshold voltages specific to different operational states of the bypass switch to manage current flow and detect potential failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single threshold voltage is used for voltage monitoring regardless of bypass switch state, then the voltage monitoring circuit is simple, but it cannot accurately detect abnormal voltages in different operational modes leading to false positives or missed detections

Engineering Contradiction:

Improvevoltage abnormality detection accuracyVSAvoidvoltage monitoring control logic

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the threshold voltage adaptive rather than fixed. The threshold voltage dynamically changes based on the bypass switch state: when the bypass switch is ON, a first threshold voltage is used; when OFF, a second threshold voltage is used. This dynamic adjustment allows accurate detection of abnormal voltages in different operational modes without false positives, resolving the contradiction between detection accuracy and system complexity.

Inventive Principle:

Principle #15Dynamics

2Reliability

If voltage monitoring is continuous with high sampling rate, then abnormal voltage can be detected quickly, but energy consumption increases

Engineering Contradiction:

Improvefailure detection capabilityVSAvoidenergy consumption of control circuit

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic action by using interrupt-driven voltage monitoring instead of continuous monitoring. The voltage monitoring circuit periodically samples the output voltage at interrupt points, checking whether it exceeds the appropriate threshold based on bypass switch state. This periodic approach maintains reliable failure detection capability while significantly reducing energy consumption compared to continuous high-rate sampling.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS9462647B2Lighting device, head light and vehicle

Publication Date: 2016.10.04 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A lighting device includes first to third output terminals, a power converter, a bypass switch, and a controller. A first light source is connected between the first and third output terminals. A second light source is connected between the second and third output terminals. The bypass switch is connected between the second and third output terminals. The controller switches the bypass switch between ON-state and OFF-state. The controller controls the power converter to adjust an output current. The controller includes a voltage meter for measuring a voltage corresponding to an output voltage of the power converter. The controller compares a measured voltage of the voltage meter with a first threshold voltage while keeping the bypass switch in OFF-state. The controller compares the measured voltage with a second threshold voltage while keeping the bypass switch in ON-state. The second threshold voltage is smaller than the first threshold voltage.